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Week 1: Think Again III: How to Reason Inductively Coursera Quiz Answers
Quiz 1: What Is Induction?
Q1. Deductive arguments are always valid.
- True
- False
Q2. Deductive validity comes in degrees.
- True
- False
Q3. Inductive strength comes in degrees.
- True
- False
Q4. Deductive validity is defeasible.
- True
- False
Q5. Inductive strength is defeasible.
- True
- False
Q6. Inductive arguments always have general conclusions.
- True
- False
Q7. Deductive arguments always provide more reason for their conclusions than inductive arguments do.
- True
- False
Q8. INSTRUCTIONS for Exercises 8 – 12: Indicate whether each of the following arguments is deductive or inductive. Assume a standard context as described. Nothing tricky!
Context: You and I want to go for a walk, but it is raining, and we do not want to walk in the rain. You ask me when I think it will stop raining. Then I say this sentence:
“The sun is coming out, so the rain will probably stop soon.”
- Deductive
- Inductive
Q9. Context: Harold is accused of a burglary, but we know him and thought he was a nice person, so we do not know whether to believe that he is guilty. Then you give this argument.
“If Harold were innocent, then he would not go into hiding. Since he is hiding, he must not be innocent.”
- Deductive
- Inductive
Q10. Context: Harold is accused of a burglary. We think that he is not guilty, but we worry that he might be punished anyway. Then I give this argument.
“If Harold is not innocent, then he will be punished. But he is innocent, so he will not be punished.”
- Deductive
- Inductive
Q11. Context: I order a cola drink at midnight. You comment that you never drink cola that late at night, because the caffeine in cola keeps you from sleeping well. I respond with this argument.
“Cola drinks never keep me awake at night. I know because I drank a cola drink just last night without any problems.”
- Deductive
- Inductive
Q12. Context: Our only son, Jeff, lives away at college. He has final exams before the winter holidays, and we are not sure when he will arrive back home. We go on a short trip to a store. The house was neat when we left, but it is messy when we return. Then you say this sentence.
“The house is a mess, so Jeff must be home from college.”
- Deductive
- Inductive
Quiz 2: Generalizations from Samples
Q1. Arguments from premises about a sample to conclusions about the whole class are valid.
- True
- False
Q2. Arguments from premises about a sample to conclusions about the whole class are defeasible.
- True
- False
Q3. Arguments from premises about a sample to conclusions about the whole class are inductive.
- True
- False
Q4. The conclusion in a generalization from a sample always begins with the word “all”.
- True
- False
Q5. Statistics are irrefutable.
- True
- False
Quiz 3: When are Generalizations Strong?
Q1. Suppose I argue that 90% of Fs in my sample are G, so 90% of all Fs are G. Then I observe more Fs in a different area and find that 90% of Fs in my new sample are also G. This new information makes my argument stronger than it was before.
- True
- False
Q2. A sample of one is always too small to justify a generalization.
- True
- False
Q3. Arguments from premises about a sample to general conclusions about the whole class commit the fallacy of hasty generalization when the sample in the premises is biased.
- True
- False
Q4. Polls are always reliable.
- True
- False
Q5. Polls are never reliable.
- True
- False
Q6. When a poll asks a question that is slanted in order to reach a certain result, then the poll does not provide strong reason to believe the desired conclusion.
- True
- False
Q7. INSTRUCTIONS FOR EXERCISES 7 – 12: Specify what, if anything, is the main problem with the following generalizations from samples. There might be more than one problem, but indicate the main one.
This philosophy class is about logic, so most philosophy classes are probably about logic.
- The sample is too small.
- The sample is biased.
- The question is slanted.
- Nothing is wrong with this argument.
Q8. Most college students like to surf, because I asked a lot of students at several colleges along the California coast, and most of them like to surf.
- The sample is too small.
- The sample is biased.
- The question is slanted.
- Nothing is wrong with this argument.
Q9. A poll asked fifty thousand randomly chosen people throughout Asia whether they would want to eat foods that have been genetically modified in ways that increase company profits but also might poison them. Less that 10% replied “Yes, definitely.” Therefore, most people in Asia do not want to eat genetically modified foods.
- The sample is too small.
- The sample is biased.
- The question is slanted.
- Nothing is wrong with this argument.
Q10. K-Mart asked all of their customers throughout the country whether they prefer K-Mart to Walmart, and 90 percent said they did. Thus, 90 percent of all shoppers in the country prefer K-Mart.
- The sample is too small.
- The sample is biased.
- The question is slanted.
- Nothing is wrong with this argument.
Q11. Most Swedes are thieves, because my bicycle has been stolen twice, and both times it was a Swede who did it.
- The sample is too small.
- The sample is biased.
- The question is slanted.
- Nothing is wrong with this argument.
Q12. I have lots and lots of friends. All of them think that I would make a great comedian. So most people in my country would probably agree that I would make a great comedian.
- The sample is too small.
- The sample is biased.
- The question is slanted.
- Nothing is wrong with this argument.
Quiz 4: Applying Generalizations
Q1. The attribute class occurs in the conclusion when we apply a generalization to a case in an argument of the form: Almost all F are G, and a is F, so a is G.
- True
- False
Q2. The reference class occurs in the conclusion when we apply a generalization to a case in an argument of the form: Almost all F are G, and a is F, so a is G.
- True
- False
Q3. An argument that applies a generalization to a case is never strong when the percentage in the premise is very low.
- True
- False
Q4. An argument that applies a generalization to show that a case has a certain property is never strong when the percentage in the premise is 50%.
- True
- False
Q5. Arguments that apply a generalization to a case are intended to be valid.
- True
- False
Q6. Arguments that apply a generalization to a case are defeasible.
- True
- False
Q7. An argument from the premise that 99% of F are G to the conclusion that this F (namely, a) is G is stronger than an argument to the same conclusion from the premise that 90% of F are G.
- True
- False
Q8. Arguments that apply a generalization to a case commit the fallacy of overlooking a conflicting reference class when another smaller reference class that was not mentioned in the argument has a very different (higher or lower) percentage of Gs that would support a conflicting conclusion.
- True
- False
Q9. INSTRUCTIONS FOR QUESTIONS 9-12: Specify what, if anything, is the main problem with the following applications of generalizations to cases. There might be more than one problem, but indicate the main one.
Almost all Prime Ministers of Great Britain have been men.;
Margaret Thatcher was Prime Minister of Great Britain.
So Margaret Thatcher is a man.
- The percentage is too low.
- The percentage is too high.
- The argument overlooks a conflicting reference class.
- Nothing is wrong with this argument.
Q10. The weather forecast says that there is only a 40% chance of rain, so it won’t rain, and we don’t need to bring an umbrella.
- The percentage is too low.
- The percentage is too high.
- The argument overlooks a conflicting reference class.
- Nothing is wrong with this argument.
Q11. Our heater works most of the time, so we can depend on it to keep us warm during the blizzard that is coming.
- The percentage is too low.
- The percentage is too high.
- The argument overlooks a conflicting reference class.
- Nothing is wrong with this argument.
Q12. Very few birds can swim, and this duck is a bird, so this duck cannot swim.
- The percentage is too low.
- The percentage is too high.
- The argument overlooks a conflicting reference class.
- Nothing is wrong with this argument.
Quiz 5: Inference to the Best Explanation
Q1. The purpose of an inference to the best explanation is to justify its conclusion.
- True
- False
Q2. Detectives use inference to the best explanation to solve murder mysteries.
- True
- False
Q3. Scientists use inference to the best explanation to draw conclusions from observations in their experiments.
- True
- False
Q4. Inferences to the best explanation are intended to be valid.
- True
- False
Q5. Inferences to the best explanation are defeasible.
- True
- False
Q6. Inferences to the best explanation are deductive.
- True
- False
Q7. Inferences to the best explanation include a premise about an observation that needs to be explained.
- True
- False
Q8. The conclusion of an inference to the best explanation is supposed to explain an observation in one of the premises.
- True
- False
Q9. One premise in an inference to the best explanation claims that one explanation is better than others.
- True
- False
Q10. If two competing explanations of the same event are equally good, then we can use an inference to the best explanation to justify belief in one of those explanations.
- True
- False
Quiz 6: Which Explanation Is Best?
Q1. One explanation is better than another when it has more of the explanatory virtues.
- True
- False
Q2. Imagine that you offer an explanation of some surprising event, and then someone criticizes your explanation by saying, “Your explanation won’t explain anything other than this particular case.” Which explanatory virtue is this critic claiming that your explanation lacks?
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q3. Imagine that you offer an explanation of some surprising event, and then someone criticizes your explanation by saying, “Your explanation conflicts with everything we know about biology.” Which explanatory virtue is this critic claiming that your explanation lacks?;
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q4. Imagine that you offer an explanation of some surprising event, and then someone criticizes your explanation by saying, “You don’t have to claim so much in order to explain what happened.” Which explanatory virtue is this critic claiming that your explanation lacks?
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q5. Imagine that you offer an explanation of some surprising event, and then someone criticizes your explanation by saying, “Your explanation just raises new questions that you also need to answer.” Which explanatory virtue is this critic claiming that your explanation lacks?
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q6. Imagine that you offer an explanation of some surprising event, and then someone criticizes your explanation by saying, “Your explanation would apply to whatever happened.” Which explanatory virtue is this critic claiming that your explanation lacks?
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q7. Indicate which explanatory virtue is the main one that is lacking from this explanation: I fished here all day, but I did not catch any fish, because there are no fish anywhere in this river.
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q8. Indicate which explanatory virtue is the main one that is lacking from this explanation: My car won’t start today, because it is mad at me for driving it so much.
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q9. Indicate which explanatory virtue is the main one that is lacking from this explanation: Her flowers won’t grow because something is wrong with them.
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q10. Indicate which explanatory virtue is lacking from this explanation: I lost the race because I just did not happen to run well today.
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Quiz 7: A Student Example: Inference to the Best Explanation
Q1. In the situation described in the student video in the lecture, which virtue of explanations would be lacking from the hypothesis that Timmy the Cat knocked the cookies off the counter because he was trying to eat one of them?
- Falsifiability
- Power or Breadth
- Modesty
- Conservativeness
Q2. In the situation described in the student video in the lecture, which virtue of explanations would be lacking from the hypothesis that ghosts knocked the cookies off the counter?
- Falsifiability
- Power or Breadth
- Modesty
- Conservativeness
Q3. In the situation described in the student video in the lecture, what is wrong with the hypothesis that a burglar knocked over the cookies after breaking in to steal something?
- It is not falsifiable.
- It cannot explain the cat hair on the counter.
- There is no evidence of anyone breaking in.
- Nothing was stolen.
- More than one of the above
Quiz 8: Arguments from Analogy
Q1. Arguments from analogy are used in art but not in science.
- True
- False
Q2. Every similarity between Earth and Mars provides some reason to believe that, since there is life on Earth, there is also life on Mars.
- True
- False
Q3. Arguments from analogy are usually intended to be valid.
- True
- False
Q4. Arguments from analogy are defeasible.
- True
- False
Q5. Arguments from analogy are inductive.
- True
- False
Q6. Arguments from analogy are stronger when the conclusion is weaker.
- True
- False
Q7. Arguments from analogy are stronger when they cite more relevant analogies between the objects.
- True
- False
Q8. Some arguments from analogy can be reconstructed as inferences to the best explanation.
- True
- False
Q9. When you give an argument from analogy, you need to specify which similarity is the one that is important for the conclusion.
- True
- False
Q10. Consider this argument from analogy to answer questions 10-12:
I have seen many movies about James Bond (007). I almost always enjoyed them. A new James Bond movie just came out. I have not seen it yet, but I know that it resembles previous James Bond movies in many respects, such as action, style, and ingenious devices. So I will probably enjoy the new James Bond movie as well, if I watch it.
Would this argument from analogy become stronger, weaker, or neither if we added a premise that the new James Bond movie has a new actor playing James Bond?
- Stronger
- Weaker
- Neither stronger nor weaker
Q11. Would the argument from analogy in Question 10 become stronger, weaker, or neither if we added a premise that the previous James Bond movies had five or fewer words in their titles, but the new James Bond movie has eight words in its title?
- Stronger
- Weaker
- Neither stronger nor weaker
Q12. Would the argument from analogy in Question 10 become stronger, weaker, or neither if we added a premise that the previous James Bond movies and new James Bond movie are also similar in more respects that I usually like, such as exotic settings, beautiful actors, intrigue, and so on?
- Stronger
- Weaker
- Neither stronger nor weaker
Q13. Consider this argument from analogy to answer questions 13-15:
A new drug cures a serious disease in rats. Rats are similar to humans in many respects. Therefore, this new drug will probably cure the same disease in humans.
Would this argument from analogy become stronger, weaker, or neither if we added a premise that the disease affects the liver, and livers in rats and in humans are very similar in structure and function?
- Stronger
- Weaker
- Neither stronger nor weaker
Q14. Would the argument from analogy in Question 13 become stronger, weaker, or neither if we added a premise that the drug does not cure this disease in monkeys or pigs?
- Stronger
- Weaker
- Neither stronger nor weaker
Q15. Would the argument from analogy in Question 13 become stronger, weaker, or neither if we added that most of the cured rats were conceived on weekdays (because that is when lab technicians were around to enable conception) whereas most humans were conceived on weekends (when they had more free time)?
- Stronger
- Weaker
- Neither stronger nor weaker
Week 2: Think Again III: How to Reason Inductively Coursera Quiz Answers
Quiz 1:Causal Reasoning
Q1. All sufficient conditions are causes.
- True
- False
Q2. When F is sufficient for G, there are no possible cases of F without G.
- True
- False
Q3. When F is necessary for G, there are no cases of G without F in normal circumstances.
- True
- False
Q4. Being a car is a sufficient condition for being a vehicle.
- True
- False
Q5. Being a car is a necessary condition for being a vehicle.
- True
- False
Q6. Being a vehicle is a sufficient condition for being a car.
- True
- False
Q7. Being a vehicle is a necessary condition for being a car.
- True
- False
Q8. Being an integer is a sufficient condition for being an even number.
- True
- False
Q9. Being an integer is a necessary condition for being an even number.
- True
- False
Q10. Being an integer is a sufficient condition for being either an even number or an odd number.
- True
- False
Q11. Cutting off Joe’s head is a sufficient condition for killing him.
- True
- False
Q12. Cutting off Joe’s head is a necessary condition for killing him.
- True
- False
Quiz 2: Negative Sufficient Condition Tests
Q1. X is not a sufficient condition of Y if there is any case in the current data where X is present and Y is absent.
- True
- False
Q2. X is a sufficient condition of Y if there is not any case in the current data where X is present and Y is absent.
- True
- False
Q3. Even if the current data include one case of X without Y, future cases still might show that X is sufficient for Y.
- True
- False
Q4. INSTRUCTIONS FOR QUESTIONS 4 – 10:
Imagine that some diners died directly after dinner. (Alliteration!) We know that something they ate caused the deaths. This is all they ate:
Alice had tomato soup, eggplant, iced tea, and cake — and Alice died.
Branden ate pea soup, chicken, water, and ice cream — and Branden did not die.
Carol had tomato soup, chicken, water, and cake — and Carol died.
Davida ate pea soup, eggplant, iced tea, and ice cream — and Davida did not die.
Ernie had tomato soup, fish, iced tea, and pie — and Ernie did not die.
Based on this data, which diner shows that eggplant is not sufficient for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q5. Based on the data in Question 4, which diner shows that tomato soup is not sufficient for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q6. Based on the data in Question 4, which diner shows that cake is not sufficient for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q7. Based on the data in Question 4, which diner shows that water is not sufficient for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q8. Based on the data in Question 4, which of the following does the case of Branden rule out as sufficient for death?
- Pea soup
- Chicken
- Water
- Ice cream
- All four of the things Branden had
- Nothing
Q9. Based on the data in Question 4, which of the following does the case of Carol rule out as sufficient for death?
- Pea soup
- Chicken
- Water
- Ice cream
- All four of the things Carol had
- Nothing
Q10. Based on the data in Question 4, which individual diner shows that something is sufficient for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q11. You can construct your own examples for practicing simply by changing the outcomes (died vs. did not die) and the foods (soup, dessert, etc.) for the diners in the data in Question 4.
- True
- False
Quiz 3: Positive Sufficient Condition Tests
Q1. A set of data can sometimes give us good reason to believe that X is a sufficient condition of Y even if that set does not include any cases where Y is absent.
- True
- False
Q2. We have good reason to believe that X is a sufficient condition of Y if (i) we have not found any case where X is present and Y is absent, (b) we have tested a wide variety of cases, including cases where X is present and cases where Y is absent, and (c) if there is any other feature that is never present where Y is absent, then we have tested cases where that other feature is absent but X is present as well as cases where that other feature is present but X is absent.
- True
- False
Q3. The positive sufficient condition test is inductive.
- True
- False
Quiz 4: Negative Necessary Condition Tests
Q1. X is not a necessary condition of Y if there is any case in the current data where X is absent and Y is present.
- True
- False
Q2. X is a necessary condition of Y if there is not any case in the current data where X is absent and Y is present.
- True
- False
Q3. Even if the current data include one case of Y without X, future cases still might show that X is necessary for Y.
- True
- False
Q4. INSTRUCTIONS FOR QUESTIONS 4 – 9:
Imagine that some diners died directly after dinner. (Alliteration!) We know that something they ate caused the deaths. This is all they ate:
Alice had tomato soup, eggplant, iced tea, and cake — and Alice died.
Branden ate pea soup, chicken, water, and ice cream — and Branden did not die.
Carol had tomato soup, chicken, water, and cake — and Carol died.
Davida ate pea soup, eggplant, iced tea, and ice cream — and Davida did not die.
Ernie had tomato soup, fish, iced tea, and pie — and Ernie did not die.
(NOTICE: This is the same data as in Question 4 of the Exercises for Lecture 7-2.)
Based on this data, which diner shows that iced tea is not necessary for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q5. Based on the data in Question 4, which diner shows that chicken is not necessary for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q6. Based on the data in Question 4, which diner shows that tomato soup is not necessary for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q7. Based on the data in Question 4, which of the following does the case of Carol rule out as necessary for death?
- Pea soup
- Eggplant
- Fish
- Iced tea
- Ice cream
- Pie
- All of the above
- Nothing
Q8. Based on the data in Question 4, which of the following does the case of Ernie rule out as necessary for death?
- Pea soup
- Eggplant
- Chicken
- Water
- Ice cream
- Cake
- All of the above
- Nothing
Q9. Based on the data in Question 4, which individual diner shows that something is necessary for death?
- Alice
- Branden
- Carol
- Davida
- Ernie
- None of these diners
Q10. There is no simple way to construct your own examples in order to practice by changing the outcomes (died vs. did not die) and the foods (soup, dessert, etc.) for the diners in the data in Question 4.
- True
- False
Quiz 5: Positive Necessary Condition Tests
Q1. We have good reason to believe that X is a necessary condition of Y if (i) we have not found any case where X is absent and Y is present, (b) we have tested a wide variety of cases, including cases where X is absent and cases where Y is present, and (c) if there are any other features that are never absent where Y is present, then we have tested cases where those other features are present but X is absent as well as cases where those other features are absent but X is present.
- True
- False
Q2. The positive necessary condition test is deductive.
- True
- False;
Quiz 6: Complex Conditions
Q1. A conjunctive condition—W and X—is not sufficient for Y if there is any case where W and X are both present but Y is absent.
- True
- False
Q2. A conjunctive condition—W and X—is not sufficient for Y if there is any case where X is present but Y is absent.
- True
- False
Q3. A disjunctive condition—W or X—is not sufficient for Y if there are any cases where X is present but Y is absent.
- True
- False
Q4. INSTRUCTIONS FOR QUESTIONS 4 – 9:
Imagine that you buy a new computer system with independent components including a new desktop computer (with a CPU and a graphics card), new software, and a new monitor. You want to play games on the new system, but it runs games very slowly. You assume that the keyboard and mouse are not creating the problem; so, to figure out what is making the system run so slowly, you experiment with combinations of your old equipment with the new equipment. Here are your experiments and results:
Experiment 1: New computer, new software, and new monitor — and it runs slowly.
Experiment 2: New computer, new software, and old monitor — and it runs fast.
Experiment 3: New computer, old software, and new monitor — and it runs fast.
Experiment 4: New computer, old software, and old monitor — and it runs fast.
Experiment 5: Old computer, new software, and new monitor — and it runs slowly.
Experiment 6: Old computer, new software, and old monitor — and it runs fast.
Experiment 7: Old computer, old software, and new monitor — and it runs slowly.
Experiment 8: Old computer, old software, and old monitor — and it runs fast.
Based on this data, which experiment shows that the new monitor is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments;
Q5. Based on the data in Question 4, which experiment shows that the conjunction of the new computer and the new monitor is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments
Q6. Based on the data in Question 4, which experiment shows that the conjunction of the new computer and the new software is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments
Q7. Based on the data in Question 4, which experiment shows that the conjunction of the new software and the new monitor is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experimients
Q8. data in Question 4, which Experiment shows that the conjunction of the old computer and the old software is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments
Q9. Based on the data in Question 4, which Experiment shows that the conjunction of the old computer and the new monitor is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments;
Quiz 7: Correlation Versus Causation
Q1. X and Y are positively correlated if the degree of X increases as the degree of Y decreases and the degree of X decreases as the degree of Y increases.
- True
- False
Q2. If X and Y are positively correlated, then they are positively correlated in all circumstances.
- True
- False
Q3. When A and B are correlated, which of the following is possible?
- A causes B.
- B causes A.
- A third thing causes both A and B.
- There is no causal relation between A and B.
- Each of the other four answers is possible.
Q4. Assume that the quality of a musician’s performance is positively correlated with how much practicing the musician did for the performance. Which of the following is most likely?
- The practice causes the quality of the performance.
- The quality of the performance causes the practice.
- A third thing causes both the practice and the quality of the performance.
- There is no causal relation between the practice and the quality of the performance.
Q5. The amount of light next to an active fire is positively correlated with the amount of heat in that location. Which of the following is most likely?
- The light causes the heat.
- The heat causes the light.
- A third thing causes both the light and the heat.
- There is no causal relation between the light and the heat.
Q6. Assume that A and B are correlated. If A changes when you manipulate B, but B does not change when you manipulate A, then which of the following is most likely? Assume normal circumstances and no interfering factors.
- A causes B.
- B causes A.
- A third thing causes both A and B.
- There is no causal relation between A and B.
Q7. Assume that A and B are correlated. If B changes when you manipulate A, but A does not change when you manipulate B, then which of the following is most likely? Assume normal circumstances and no interfering factors.
- A causes B.
- B causes A.
- A third thing causes both A and B.
- There is no causal relation between A and B.;
Quiz 8: Causal Fallacies
Q1. An argument commits the fallacy called “post hoc, ergo propter hoc” when it concludes that A causes B from the premise that A occurred before B.
- True
- False
Q2. An argument confuses cause with effect when it uses a correlation to argue that A causes B when actually B causes A.
- True
- False
Q3. The fallacy of confusing cause and effect occurs only in science.
- True
- False
Q4. Consider this argument: After I argued that Johnson is the best candidate for President, she said that she supports Johnson, too. So she must have been convinced by my arguments.
Which of the following fallacies does it commit?
- Post Hoc Ergo Propter Hoc
- Confusing Cause with Effect
- Neither of the Above;
Week 3: Think Again III: How to Reason Inductively Coursera Quiz Answers
Quiz 1: Why Probability Matters
Q1. If a fair coin comes up heads five times in a row, then the probability that it will come up heads on the next flip is:
- One half (0.5)
- Less than one half
- More than one half (> 0.5)
Q2. If a fair dealer deals you five cards out of a shuffled fair standard deck of cards, then which of the following hands is most likely?
- Ace of Hearts, King of Hearts, Queen of Hearts, Jack of Hearts, and Ten of Hearts
- Ace of Hearts, King of Hearts, Queen of Hearts, Jack of Hearts, and Five of Clubs
- Ace of Hearts, Jack of Hearts, Nine of Diamonds, Seven of Clubs, and Five of Clubs
- All of these hands are equally likely.
Q3. As described in the lecture, Linda is thirty-one years old, single, outspoken, and very bright. As a student, she majored in philosophy, was deeply concerned with issues of discrimination and social justice, and also participated in antinuclear demonstrations. Which of the following is most likely?
- Linda is a bank teller.
- Linda is a bank teller who is active in the feminist movement.
- These possibilities are equally likely.
Q4. Imagine that you are playing the old television game show “Let’s Make a Deal” hosted by Monte Hall and described in the lecture. You face three closed doors. Behind one of the doors is a car. Behind each of the other two doors is a goat. You pick door A, so you will get to keep what is behind door A if you stick with it. Then, as always, Monte Hall opens one of the remaining two doors, reveals a goat behind that other door, and offers you the opportunity to switch doors, if you want. Suppose that this time Monte Hall opens door C and offers you the opportunity to switch to door B. If you switch doors, then you will get what is behind door B instead of what is behind door A. If you do not switch doors, then you will get what is behind door A. Should you switch doors?
- You should switch doors.
- You should not switch doors.
- It does not matter whether or not you switch doors.;
Quiz 2: What Is Probability?
Q1. If the probability of an event is 0.73, then its probability can also be expressed as
- 73% chance
- 73 out of 100
- 7.3 out of 10
- All of the above
- None of the above
Q2. It is possible for some events to have a probability of
- 1.5
- –1.5
- Both of the above are possible for different events.
- None of the above.
Q3. If the probability of an event is 1.0, then
- It is certain that it will happen.
- It is certain that it will not happen.
- It might or might not happen.
Q4. When someone assumes that six-sided dice are equally likely to fall on any of the sides—1, 2, 3, 4, 5, or 6—then that person is calculating
- A priori probability
- Statistical probability
- Subjective probability
Q5. When a coin is bent, the most accurate way to determine the probability that it will land heads up when it is flipped is to use:
- A priori probability
- Statistical probability
- Subjective probability;
Q6. A coin flip is fair when the coin is equally likely to land with either side—heads or tails—up, and the coin will always land on either heads or tails but not on its edge. If we assume that a coin flip is fair, then the probability that the coin will land heads up is:
- 0
- 0.25
- 0.5
- 0.75
- 1
Q7. A roll of a six-sided die is fair when the die is equally likely to land with any of its sides—1, 2, 3, 4, 5, or 6—up, and the die will always land with one of those sides up. If we assume that a roll of a six-sided die is fair, then the probability that the die will land with 4 up is:
- 0
- 1/6
- 3/6
- 4/6
- 1
Q8. A roll of a ten-sided die is fair when the die is equally likely to land with any of its sides—1, 2, 3, 4, 5, 6, 7, 8, 9, or 10—up, and the die will always land with one of those sides up. If we assume that a roll of a ten-sided die is fair, then the probability that the die will land with 4 up is:
- 0
- 1/10
- 3/10
- 4/10
- 1
Q9. A roll of two dice is X when the sum of the numbers on the two sides that land up is X. If we assume that the roll is fair, what is the probability that one roll of two six-sided dice will be 4 (that is, will land with a total of 4 up)?
- 0
- 3/36
- 3/6
- 4/6
- A1;
Quiz 3: Negation
Q1. If the probability that a flipped coin will land heads up is 0.5, what is the probability that it will NOT land heads up?
- 0
- 0.25
- 0.5
- 0.75
- 1.0
Q2. Imagine that you bend the coin in Question 1 so that the probability that it will land heads up when flipped is 0.25. Now what is the probability that it will NOT land heads up?
- 0
- 0.25
- 0.5
- 0.75
- 1.0
Q3. As shown in Lecture 8-02, the probability of rolling a seven on two fair six-sided dice is 6/36. What is the probability of NOT rolling a seven on two fair six-sided dice?
- 0
- 6/36
- 18/36
- 30/36
- 1.0
Q4. The probability of picking an ace at random out of a fair standard deck of cards is 1/13. What is the probability of NOT picking an ace out of this deck?
- 0
- 1/13
- 9/13
- 12/13
- 1.0
Q5. The probability of picking a spade at random out of a fair standard deck of cards is 1/4. What is the probability of NOT picking a spade at random out of this deck?
- 0
- 1/4
- 2/4
- 3/4
- 1.0
Q6. Imagine that you own one ticket to a lottery where the chances of this ticket winning are one in 1,000,000. What is the probability of this ticket NOT winning?
- 0
- 1/1,000,000
- 9/10
- 999,999/1,000,000
- 1.0
Q7. If the probability of an event is 0.1, what is the probability that either that event will occur or that event will not occur?
- 0
- 0.1
- 0.5
- 0.9
- 1.0;
Quiz 4: Conjunction
Q1. Two events are independent (in the sense used in the rules for probability) if and only if
- They cannot possibly both occur together.
- Whether or not one of the events occurs does not affect the probability that the other event will occur.
- Neither of the events depends on anything else in order to occur.
Q2. If two events are independent, then the probability of both events occurring is
- The sum of the probability of the first event plus the probability of the second event.
- The difference of the probability of the first event minus the probability of the second event.
- The product of the probability of the first event times the probability of the second event.
Q3. If two events are NOT independent, then the probability of both events occurring is
- The product of the probability of the first event times the probability of the second event.
- The product of the probability of the first event times the probability of both the first event and the second event.
- The product of the probability of the first event times the conditional probability of the second event given the first event.
- The product of the probability of the first event times the conditional probability of the first event given the second event.
Q4. The conditional probability of one event (X) given another event (Y) is:
- The percentage of cases where X occurs out of the cases where Y occurs.
- The percentage of cases where Y occurs out of the cases where X occurs.
- The probability that both X and Y occur.
Q5. Assuming that all coin flips here are fair, the flip of one coin and the flip of another coin are:
- Independent
- Not independent
- Sometimes independent and sometimes not independent
Q6. Assuming that all coin flips here are fair, what is the probability of getting tails on two flips in a row of the same coin?
- 0
- 0.25
- 0.5
- 0.75
- 1
Q7. Assuming that all dice rolls here are fair, what is the probability of getting three on both dice (that is, 3 on one and also 3 on the other for a total of 6) when you roll two 6-sided dice at the same time?
- 0
- 1/36
- 1/6
- 2/6
- 1
Q8. Assuming that all card picks here are fair, what is the probability of getting a spade on two picks out of a standard deck when you replace the card that you picked first and shuffle the deck before you pick the second card?
- 1/16
- 2/4
- 1
- 0
- 1/4
Q9. Assuming that all card picks here are fair, when you pick two cards out of a deck, and you do not replace the card that you picked first before you pick the second card, then the probabilities of getting a Jack on both picks are:
- Independent
- Not independent
- Sometimes independent and sometimes not independent
Q10. Assuming that all card picks here are fair, imagine that you pick a King of Hearts out of a standard deck, and you do not put that card back in the deck, then what is the probability that you will pick a Queen on the next pick out of the remaining deck?
- 4/52
- 4/52 x 4/52
- 4/51
- 4/52 x 4/51;
Q11. Assuming that all card picks here are fair, imagine that you pick a Queen of Hearts out of a standard deck, and you do not put that card back in the deck, then what is the probability that you will pick a Queen on the next pick out of the remaining deck?
- 4/52
- 4/51
- 3/52
- 3/51
Q12. Assuming that all card picks here are fair, what is the probability that you will pick a King and then a Queen out of a standard deck when you do not put the card that you picked first back in the deck?
- 4/52
- 4/52 x 4/52
- 4/51
- 4/52 x 4/51
Q13. Assuming that all card picks here are fair, what is the probability that you will pick two Queens in two draws out of a standard deck when you do not put the card that you picked first back in the deck:
- 4/52 x 4/52
- 4/52 x 4/51
- 4/52 x 3/52
- 4/52 x 3/51
Q14. Assuming that all card picks here are fair, what is the probability that you will pick a Spade and then a Heart out of a standard deck when you do not put the card that you picked first back in the deck?
- 4/52 x 4/51
- 4/52 x 4/52
- 13/52 x 13/51
- 13/52 x 13/52
Q15. You can construct your own examples for practicing simply by asking about other outcomes on flips of coins, rolls of dice, and picks of cards.
- QuizTrue
- False
Quiz 5: Disjunction
Q1. Two events are mutually exclusive if and only if
- They cannot possibly both occur together.
- Whether or not one of the events occurs does not affect the probability that the other event will occur.
- Neither of the events excludes anything else.
Q2. If two events are mutually exclusive, then the probability of either one event or the other event occurring is
- The sum of the probability of the first event plus the probability of the second event.
- The difference of the probability of the first event minus the probability of the second event.
- The product of the probability of the first event times the probability of the second event.
Q3. If two events are NOT mutually exclusive, then the probability of either one event or the other event occurring is
- The sum of the probability of the first event plus the probability of the second event.
- The sum of the probability of the first event plus the probability of both the first event and the second event.
- The sum of the probability of the first event plus the probability of the second event minus the probability of both the first event and the second event occurring together.
- The sum of the probability of the first event plus the conditional probability of the first event given the second event.
Q4. On one fair flip of a single coin, getting heads and getting tails are:
- Mutually exclusive
- Not mutually exclusive
- Sometimes mutually exclusive and sometimes not mutually exclusive
Q5. On one fair flip of a single coin, what is the probability of getting either heads or tails?
- 0
- 0.25
- 0.5
- 0.75
- 1;
Q6. Assuming that all dice rolls here are fair, what is the probability of getting either two or three when you roll one 6-sided die?
- 0
- 1/6
- 2/6
- 3/6
- 1
Q7. Assuming that all dice rolls here are fair, what is the probability of getting three on either one die or the other die when you roll two 6-sided dice at the same time?
- 1/36
- 1/6
- 2/6
- 2/6 – 1/36
- 2/6 + 1/36
Q8. Assuming that all card picks here are fair, what is the probability of getting either a spade or a club when you pick one card out of a standard deck?
- 0
- 1/4
- 2/4
- 3/4
- 1
Q9. Assuming that all card picks here are fair, what is the probability of picking a spade on either the first pick or the second pick when you pick two cards out of a standard deck (and when you put the first card back and shuffle the cards before the second pick)?
- 1/16
- 1/4
- 2/4
- 2/4 – 1/16
- 2/4 + 1/16;
Q10. Assuming that all card picks here are fair, what is the probability of getting either a six or a seven when you pick one card out of a standard deck?
- 0
- 1/13
- 2/13
- 3/13
- 1
Q11. Assuming that all card picks here are fair, what is the probability of picking a seven on either the first pick or the second pick when you pick two cards out of a standard deck (and when you put the first card back and shuffle the cards before the second pick)?
- 1/13 x 1/13
- 1/13
- 2/13
- 2/13 – (1/13 x 1/13)
- 2/13 + (1/13 x 1/13)
Q12. Which of the following is accurate?
- Order of events matters in combinations but not in permutations.
- Order of events matters in permutations but not in combinations.
- Order of events matters in both combinations and permutations.
- Order of events matters in neither combinations nor permutations.
Q13. Assuming that all card picks here are fair, what is the probability of picking an eight and a nine in any order when you pick two cards out of a standard deck (when you put the first card back and shuffle the cards before the second pick)?
- 1/13 x 1/13
- 1/13 + 1/13
- 2/13 + 2/13
- (1/13 x 1/13) + (1/13 x 1/13)
- (1/13 + 1/13) x (1/13 + 1/13)
Q14. Imagine that there are two little lotteries in your town. Each lottery sells exactly 100 tickets each and has only one winning ticket. You pick one of these lotteries and buy two tickets to the same lottery. What is the probability that you will have one winning ticket (that is, the probability that either your first ticket or your second ticket will win)?
- 1/100
- 1/100 x 1/100
- 1/100 + 1/100
- 1/100 + 1/100 – (1/100 x 1/100)
- (1/100 x 1/100) – (1/100 + 1/100)
Q15. As in Question 14, imagine that there are two little lotteries in your town. Each lottery sells exactly 100 tickets each and has only one winning ticket. You buy one ticket to each of these two lotteries. What is the probability that you will have at least one winning ticket (that is, the probability that either your first ticket, your second ticket, or both will win)?
- 1/100
- 1/100 x 1/100
- 1/100 + 1/100
- 1/100 + 1/100 – (1/100 x 1/100)
- (1/100 x 1/100) – (1/100 + 1/100)
Q16. You can construct your own examples for practicing simply by asking about other outcomes on flips of coins, rolls of dice, and picks of cards.
- True
- False;
Quiz 6: Series
Q1. What is the probability of getting heads at least once in a series of three fair flips of a coin?
- 0.125
- 0.25
- 0.5
- 0.75
- 0.875
Q2. What is the probability of rolling seven at least once in a series of three fair rolls of two dice in each roll?
- 1/6
- 1/3
- 5/6
- 91/216
- 125/216
Q3. What is the probability of drawing at least one spade in a series of four consecutive fair draws from a standard deck of cards, when the card drawn is returned to the deck and the deck is shuffled between each draw?
- 1/16
- 1/4
- 3/4
- 81/256
- 175/256
Q4. You can construct your own examples for practicing simply by asking about other series of flips of coins, rolls of dice, and picks of cards.
- True
- False;
Quiz 7: Bayes Theorem (Optional)
Q1. A FALSE POSITIVE (or a false alarm) is
- A case where the condition is present and the test comes out positive.
- A case where the condition is present and the test comes out negative.
- A case where the condition is absent and the test comes out positive.
- A case where the condition is absent and the test comes out negative.
Q2. A FALSE NEGATIVE (or a miss) is
- A case where the condition is present and the test comes out positive.
- A case where the condition is present and the test comes out negative.
- A case where the condition is absent and the test comes out positive.
- A case where the condition is absent and the test comes out negative.
Q3. The BASE RATE or PREVALENCE of a condition in a population is
- The number of people in the population.
- The percentage of the population with the condition.
- The probability of a positive test result, given that the person tested does have the condition.
- The probability of a negative test result, given that the person tested does not have the condition.
Q4. The SENSITIVITY of a test for a condition is
- The probability of a positive test result.
- The probability of a negative test result.
- The probability of a positive test result, given that the person tested does have the condition.
- The probability of a negative test result, given that the person tested does not have the condition.
Q5. The SPECIFICITY of a test for a condition is
- The probability of a positive test result.
- The probability of a negative test result.
- The probability of a positive test result, given that the person tested does have the condition.
- The probability of a negative test result, given that the person tested does not have the condition.;
Q6. INSTRUCTIONS FOR QUESTIONS 6–14:
Assume that
(A) The base rate or prevalence of colon cancer in a population is 0.1% or 0.001.
(B) The sensitivity of a certain test for colon cancer is 90%. (Sensitivity is the probability of a positive test result, given that the person tested does have colon cancer.)
(C) The specificity of that same test for colon cancer is 97%. (Specificity is the probability of a negative test result, given that the person tested does not have colon cancer.)
Use these ASSUMPTIONS to fill the boxes in this TABLE:
What number belongs in Box 7?
- 10
- 90
- 100
- 1000
- 99,900
Q7. What number belongs in Box 8?
- 10
- 90
- 100
- 1000
- 99,900
Q8. What number belongs in Box 1?
- 10
- 90
- 100
- 1000
- 99,900
Q9. What number belongs in Box 4?
- 10
- 90
- 100
- 1000
- 99,900
Q10. What number belongs in Box 5?
- 2997
- 3087
- 96,903
- 99,000
- 99,900
Q11. What number belongs in Box 2?
- 2997
- 3087
- 96,903
- 99,000
- 99,900
Q12. What number belongs in Box 3?
- 90
- 2997
- 3087
- 96,903
- 96,913
Q13. What number belongs in Box 6?
- 10
- 2997
- 3087
- 96,903
- 96,913
Q14. In the case described in Question 6, what is the probability that a patient has colon cancer given that the patient tests positive for colon cancer with this test?
- 10/3087
- 90/3087
- 100/3087
- 2997/3087
- 90/100,000;
Q15. Suppose that the situation is exactly like the case in Question 6 except that the base rate is higher:
- (A) The base rate or prevalence of colon cancer in a population is 10% or 0.1.
- (B) The sensitivity of a certain test for colon cancer is 90%. (Sensitivity is the probability of a positive test result, given that the person tested does have colon cancer.)
- (C) The specificity of that same test for colon cancer is 97%. (Specificity is the probability of a negative test result, given that the person tested does not have colon cancer.)
For this population and test, what is the probability that a patient has colon cancer given that the patient tests positive for colon cancer with this test?
- 27/90
- 27/117
- 90/117
- 10/883
- 873/883
Q16. Suppose that the situation is exactly like the case in Question 6 except that the sensitivity is higher:
- (A) The base rate or prevalence of colon cancer in a population is 0.1% or 0.001.
- (B) The sensitivity of a certain test for colon cancer is 99%. (Sensitivity is the probability of a positive test result, given that the person tested does have colon cancer.)
- (C) The specificity of that same test for colon cancer is 97%. (Specificity is the probability of a negative test result, given that the person tested does not have colon cancer.)
For this population and test, what is the probability that a patient has colon cancer given that the patient tests positive for colon cancer with this test?
- 1/99
- 99/2997
- 99/3096
- 2997/3096
- 96,903/96,904
Q17. Suppose that the situation is exactly like the case in Question 6 except that the specificity is higher:
- (A) The base rate or prevalence of colon cancer in a population is 0.1% or 0.001.
- (B) The sensitivity of a certain test for colon cancer is 90%. (Sensitivity is the probability of a positive test result, given that the person tested does have colon cancer.)
- (C) The specificity of that same test for colon cancer is 99%. (Specificity is the probability of a negative test result, given that the person tested does not have colon cancer.)
For this population and test, what is the probability that a patient has colon cancer given that the patient tests positive for colon cancer with this test?
- 90/999
- 90/1089
- 999/1089
- 10/98,911
- 98,901/98,911
Q18. Suppose that a patient tests positive for colon cancer in the circumstances of Question 17, so there is an 8% chance that this patient has colon cancer. This information puts the patient in a new population—patients who have tested positive for colon cancer—with a higher base rate (8%) of colon cancer. Now suppose that the doctor orders a second test that is independent of the first test (because it looks for separate indications of colon cancer). This second test has the same specificity and sensitivity as the first test, so this new situation is:
(A) The base rate or prevalence of colon cancer in a population is 8% or 0.08.
(B) The sensitivity of the second test for colon cancer is 90%. (Sensitivity is the probability of a positive test result, given that the person tested does have colon cancer.)
(C) The specificity of the second test for colon cancer is 99%. (Specificity is the probability of a negative test result, given that the person tested does not have colon cancer.)
For this population and test, what is the probability that a patient has colon cancer given that the patient tests positive for colon cancer with this test?
- 920/7200
- 920/8120
- 7200/8120
- 800/91,880
- 91,080/91,880
Q19. Chris tested positive for cocaine once in a random screening test. This test has a sensitivity and specificity of 90%, and 10 percent the students in Chris’s school use cocaine. What is the probability that Chris really did use cocaine?
- 90/180
- 90/90
- 10/820
- 10/810
- 810/820
Q20. Late last night a car ran into your neighbor and drove away. In your town, there are 500 cars, and 2% of them are Porsches. The only eyewitness to the incident says that the car that hit your neighbor was a Porsche. Tested under similar conditions, the eyewitness mistakenly classifies cars of other makes as Porsches 10% of the time, and correctly classifies Porsches as Porsches 80% of the time. What are the chances that the car that hit your neighbor really was a Porsche?
- 8/49
- 8/57
- 49/57
- 2/443
- 441/443
Q21. You can construct your own examples for practicing simply by asking about other cases with different base rates, sensitivities, and specificities.
- True
- False
Quiz 8: Expected Financial Value
Q1. The expected financial value of a bet is:
- The net gain of winning minus the net loss of losing
- The probability of winning minus the probability of losing
- The probability of winning times the net gain of winning minus the probability of losing times the net loss of losing
- The probability of winning times the net loss of losing minus the probability of losing times the net gain of winning
Q2. INSTRUCTIONS FOR QUESTIONS 2 – 8: In the following games, you lay down $1 to bet that you will pick a certain card in a fair draw from a standard deck. If you lose, then you lose your $1. If you win, then you collect the gross amount indicated, so your net gain is $1 less.
What is the expected financial value of a bet where you will win $26 if you draw a seven of spades?
- –$1
- –$0.50
- $0
- $25/52
- $0.50
Q3. What is the expected financial value of a bet where you will win $26 if you draw either a seven of spades or a seven of clubs?
- –$0.50
- $0
- $25/52
- $0.50
- $1
Q4. What is the expected financial value of a bet where you will win $26 if you draw a seven of any suit?
- –$0.50
- $0
- $25/52
- $0.50
- $1
Q5. What is the expected financial value of a bet where you will win $4 if you draw either a Jack, a Queen, or a King?
- –$4/52
- $0
- $8/52
- $36/52
- $48/52;
Q6. What is the expected financial value of a bet where you will win $2 if you do NOT draw either a Jack, a Queen, or a King?
- –$4/52
- $0
- $28/52
- $40/52
- $68/52
Q7. What is the expected financial value of a bet where you will win $2652 if you draw a seven of spades and then a seven of clubs on two consecutive draws (without returning the first card to the deck)?
- –$52/2704
- –$52/2652
- $0
- $1/2652
- $52/2704
Q8. What is the expected financial value of a bet where you will win $2652 if you draw a seven of spades and then a seven of clubs on two consecutive draws (where you replace the card and shuffle the deck between draws)?
- –$52/2704
- –$52/2652
- $0
- $1/2652
- $52/2704
Q9. You can construct your own examples for practicing simply by asking about other bets.
- True
- False;
Quiz 9: Expected Overall Value
Q1. Imagine that you are going to the drugstore to buy medicine for a friend. Your friend will die if you do not get the medicine on this trip to the drugstore, and nobody else will loan you money for the medicine. You have only $10 with you, and this is exactly what the medicine costs. Outside the drugstore is a young man playing three-card monte, a simple game in which the dealer shows you three cards, turns them over, shifts them briefly from hand to hand, and then lays them out, facedown, on the top of a box. You are supposed to identify a particular card; and, if you do, you are paid even money. You yourself are a magician and know the sleight-of-hand trick that fools most people, and you are sure that you can guess the card correctly nine times out of ten. In this situation, what is the expected financial value of a bet of $10?
- $0
- $8
- $9
- $10
- $20
Q2. Should you play the game in the circumstances in Question 1?
- Yes, you should play the game.
- No, you should not play the game .
- It is reasonable either to play or not to play to game.
Q3. In the game of ignorance, you draw one card from a deck. You do not know how many cards or which kinds of cards are in the deck. It might be a standard deck or it might contain only diamonds or only aces of spades or any other combination of cards. It costs nothing to play. If you bet that the card you draw will be a spade, and it is a spade, then you win $100. What is the expected financial value of playing this game?
- $1
- $25
- $100
- $400
- There is no way to calculate expected financial value in this game.
Q4. Consider the following game: You flip a coin continuously until you get tails once. If you get no heads (tails on the first flip), then you are paid nothing. If you get one heads (tails on the second flip), then you are paid $2. If you two heads (tails on the third flip), then you are paid $4. If you get three heads (tails on the fourth flip), then you are paid $8. If you get four heads (tails on the fifth flip), then you are paid $16. And so on. The general rule is that, for any number n, if you get n heads before your first tails, then you are paid $2n (that is, 2 to the nth power dollars). What is the expected monetary value of this game?
- $2
- $4
- $8
- $16
- Infinite
Q5. How much should you pay to play the game in the previous exercise?
- $0
- $2
- $4
- $8
- $16
- All of your savings
- Who knows?;
Week 4: Think Again III: How to Reason Inductively Coursera Quiz Answers
Quiz 1: Final Quiz
Q1. Deductive
validity comes in degrees.
- True
- False
Q2. Inductive strength is not defeasible.
- True
- False
Q3. Arguments
that apply generalizations to particular cases are
- Deductive
- Inductive
- Both deductive and
inductive - Neither deductive nor
inductive
Q4. An
argument that generalizes from a sample to a whole class is stronger (other
things being equal) when
- Its premises are
false - The sample is
smaller - The sample is unbiased
- All of the above
- None of the above
Q5. Specify the main
problem with the following generalization from a sample. There might be more
than one problem, but indicate the most important one.
A poll asked 100,000 randomly chosen people in Ecuador, Kenya, and Indonesia—
representing three continents—whether they own a winter coat. Less than 20%
said they did. Therefore, most people on Earth do not own a winter coat.
- The sample is too small
- The sample is biased
- The question is
slanted - Nothing is wrong with
this argument;
Q6. An
argument of the form “X% of Fs are Gs, a is an F, so a is probably NOT a G” is
strongest when X is:
- 10%
- 30%
- 50%
- 70%
- 90%
Q7. Consider this
argument: 90% of Chinese people like fish, and Manto is Chinese, so Manto
probably likes fish.
Would this argument be stronger or weaker if we added the
information that Manto is from a region of China where most people do not like
fish?
- Stronger
- Weaker
- Neither stronger nor weaker
Q8. If
two explanations are equal in all other respects, then
- The more conservative
explanation is better - The less conservative
explanation is better - Whether the
explanation is more or less conservative does not affect how good it is as an
explanation
Q9. Indicate which
explanatory virtue is lacking from this explanation:
Jing moved to Taiwan
because she wanted to.
- Falsifiability
- Conservativeness
- Power (or Breadth)
- Depth
- Modesty
Q10. Consider this
argument from analogy: I have visited many public gardens, and I almost always
enjoyed walking in them. I just moved to a new town with a public garden. I
have not visited it yet, but I know that it is similar in many ways to other
public gardens that I have visited. So I will probably enjoy walking in the new
public garden as well.
Would this argument from analogy become stronger, weaker, or neither if we
added a premise that the new public garden is a rock garden, but none of the
gardens that I visited before were rock gardens?
- Stronger
- Weaker
- Neither stronger nor weaker
Q11. Being a bird is
- Necessary but not
sufficient for being a swan - Sufficient but not
necessary for being a swan - Both necessary and
sufficient for being a swan - Neither necessary nor
sufficient for being a swan
Q12. Imagine that you buy
a new computer system with independent components including a new desktop
computer (with a CPU and a graphics card), new software, and a new monitor. You
want to play games on the new system, but it runs games very slowly. You assume
that the keyboard and mouse are not creating the problem; so, to figure out
what is making the system run so slowly, you experiment with combinations of
your old equipment with the new equipment. Here are your experiments and
results:
Experiment 1: New computer, new software, and new monitor — and it runs slowly.
Experiment 2: New computer, new software, and old monitor — and it runs slowly.
Experiment 3: New computer, old software, and new monitor — and it runs fast.
Experiment 4: New computer, old software, and old monitor — and it runs fast.
Experiment 5: Old computer, new software, and new monitor — and it runs slowly.
Experiment 6: Old computer, new software, and old monitor — and it runs fast.
Experiment 7: Old computer, old software, and new monitor — and it runs fast.
Experiment 8: Old computer, old software, and old monitor — and it runs fast.
Based on this data, which experiment shows that the new software is NOT SUFFICIENT
for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments
Q13. Imagine that you buy
a new computer system with independent components including a new desktop
computer (with a CPU and a graphics card), new software, and a new monitor. You
want to play games on the new system, but it runs games very slowly. You assume
that the keyboard and mouse are not creating the problem; so, to figure out
what is making the system run so slowly, you experiment with combinations of
your old equipment with the new equipment. Here are your experiments and
results:
Experiment 1: New computer, new software, and new monitor — and it runs slowly.
Experiment 2: New computer, new software, and old monitor — and it runs fast.
Experiment 3: New computer, old software, and new monitor — and it runs slowly.
Experiment 4: New computer, old software, and old monitor — and it runs fast.
Experiment 5: Old computer, new software, and new monitor — and it runs fast.
Experiment 6: Old computer, new software, and old monitor — and it runs fast.
Experiment 7: Old computer, old software, and new monitor — and it runs slowly.
Experiment 8: Old computer, old software, and old monitor — and it runs fast.
Based on this data, which experiment shows that the new computer is NOT
NECESSARY for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments
Q14. Imagine that you buy
a new computer system with independent components including a new desktop
computer (with a CPU and a graphics card), new software, and a new monitor. You
want to play games on the new system, but it runs games very slowly. You assume
that the keyboard and mouse are not creating the problem; so, to figure out
what is making the system run so slowly, you experiment with combinations of
your old equipment with the new equipment. Here are your experiments and
results:
Experiment 1: New computer, new software, and new monitor — and it runs slowly.
Experiment 2: New computer, new software, and old monitor — and it runs slowly.
Experiment 3: New computer, old software, and new monitor — and it runs fast.
Experiment 4: New computer, old software, and old monitor — and it runs fast.
Experiment 5: Old computer, new software, and new monitor — and it runs fast.
Experiment 6: Old computer, new software, and old monitor — and it slowly.
Experiment 7: Old computer, old software, and new monitor — and it runs fast.
Experiment 8: Old computer, old software, and old monitor — and it runs fast.
Based on this data, which experiment shows that the conjunction of the new
computer and the old monitor is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of the above;
Q15. Imagine that you buy
a new computer system with independent components including a new desktop
computer (with a CPU and a graphics card), new software, and a new monitor. You
want to play games on the new system, but it runs games very slowly. You assume
that the keyboard and mouse are not creating the problem; so, to figure out
what is making the system run so slowly, you experiment with combinations of
your old equipment with the new equipment. Here are your experiments and
results:
Experiment 1: New computer, new software, and new monitor — and it runs slowly.
Experiment 2: New computer, new software, and old monitor — and it runs slowly.
Experiment 3: New computer, old software, and new monitor — and it runs fast.
Experiment 4: New computer, old software, and old monitor — and it runs fast.
Experiment 5: Old computer, new software, and new monitor — and it runs slowly.
Experiment 6: Old computer, new software, and old monitor — and it runs fast.
Experiment 7: Old computer, old software, and new monitor — and it runs fast.
Experiment 8: Old computer, old software, and old monitor — and it runs fast.
Based on this data, which experiment shows that the conjunction of the new
software and the new monitor is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments
Q16. Imagine that you buy
a new computer system with independent components including a new desktop
computer (with a CPU and a graphics card), new software, and a new monitor. You
want to play games on the new system, but it runs games very slowly. You assume
that the keyboard and mouse are not creating the problem; so, to figure out
what is making the system run so slowly, you experiment with combinations of
your old equipment with the new equipment. Here are your experiments and
results:
- Experiment 1: New computer, new software, and new monitor — and it runs slowly.
- Experiment 2: New computer, new software, and old monitor — and it runs slowly.
- Experiment 3: New computer, old software, and new monitor — and it runs fast.
- Experiment 4: New computer, old software, and old monitor — and it runs fast.
- Experiment 5: Old computer, new software, and new monitor — and it runs slowly.
- Experiment 6: Old computer, new software, and old monitor — and it runs fast.
- Experiment 7: Old computer, old software, and new monitor — and it runs fast.
- Experiment 8: Old computer, old software, and old monitor — and it runs fast.
Based on this data, which experiment shows that the conjunction of the new
computer and the new software is not sufficient for the system to run slowly?
- Experiment 1
- Experiment 2
- Experiment 3
- Experiment 4
- Experiment 5
- Experiment 6
- Experiment 7
- Experiment 8
- None of these experiments
Q17. If
there is no case of a candidate (X) without the target (Y) in a data set, then
that data provides reason to believe the conclusion that the candidate (X) is
sufficient for the target (Y).
- True
- False
Q18. If
A is positively correlated with B, then
- A causes B
- B causes A
- A third thing causes
A and also causes B - Any of the other
answers might be true
Q19. Assume that A and B
are highly correlated. If A changes when you manipulate B, but B does not
change when you manipulate A, then which of the following is most likely?
Assume normal circumstances and no interfering factors.
- A causes B
- B causes A
- A third thing causes
both A and B - There is no causal
relation between A and B
Q20. When
dice are irregular so that the sides of the dice are not equal in size or
weight, then the most accurate way to determine the probability that they will
land with a certain side (such as 5) up is to use:
- A priori probability
- Statistical
probability - Subjective
probability;
Q21. If
the probability of a method of contraception working to prevent conception is
0.9, then what is the probability that it will not work?
- 0
- 0.1
- 0.5
- 0.9
- 1.0
Q22. Assume that you and
your neighbor will drive separately to work today. You have a 1% chance of getting
into an accident on the way to work today, and your neighbor has a 2% chance of
getting into an accident on the way to work today. Whether one of you has an
accident does not affect the probability that the other will have an accident
(because you drive opposite directions, the weather is not conducive to
accidents, etc.). What is the probability that both you and your neighbor will
have an accident on the way to work today?
- 0.00001
- 0.00002
- 0.01
- 0.02
- 0.1
- 0.2
Q23. Assume that there is
a 50% chance of rain on this Saturday in your city and a 50% chance of rain on
this Sunday in your city. If the rain storm hits your city, then it will be
likely to stay for more than one day, so there is an 80% chance of rain on this
Sunday, given that it rained on this Saturday. What is the probability that it
will rain on both this Saturday and this Sunday in your city?
- 0.04
- 0.2
- 0.4
- 0.5
- 0.8
Q24. Imagine that there is a 10% chance that you eat dinner
tonight before 6:00 p.m. and a 30% chance that you eat dinner tonight after
9:00 p.m. Assume that you eat dinner tonight only once. What is the probability
that you will eat dinner tonight either before 6:00 p.m. or after 9:00 p.m.?
- 0.03
- 0.1
- 0.3
- 0.37
- 0.4
Q25. Imagine that there is
a 60% chance of rain today in Delhi, India, and a 90% chance of rain today in
Paris, France. Also assume that the probabilities of rain today in Delhi and in
Paris are independent. What is the probability that it will rain today in either
Delhi or Paris (that is, in at least one of these cities)?
- 0.54
- 0.6
- 0.9
- 0.96
- 1.5
Q26. What
is the probability of rolling twelve at least once in a series of three fair
rolls of two six-sided dice in each roll?
- 1/36 + 1/36 + 1/36
- 35/36 + 35/36 + 35/36
- 35/36 x 35/36 x 35/36
- 1 – (35/36 x 35/36 x
35/36) - 1 – (1/36 x 1/36 x
1/36)
Q27. In the following game, you lay down $1 to bet that you
will pick a certain card in a fair draw from a standard deck. If you lose, then
you lose your $1. If you win, then you collect the gross amount indicated, so
your net gain is $1 less. What is the expected financial value of a bet where
you will win $2 if you draw a diamond?
- – $3/4
- – $2/4
- – $1/4
- $1/4
- $2/4
Q28. In the following
game, you lay down $1 to bet that you will pick a certain card in a fair draw
from a standard deck. If you lose, then you lose your $1. If you win, then you
collect the gross amount indicated, so your net gain is $1 less. What is the
expected financial value of a bet where you will win $52 if you draw a Queen of
Hearts?
- – $51/52
- – $1/52
- $0
- $1/52
- $51/52
Q29. In the following
game, you lay down $1 to bet that you will pick a certain card in a fair draw
from a standard deck. If you lose, then you lose your $1. If you win, then you
collect the gross amount indicated, so your net gain is $1 less. What is the
expected financial value of a bet where you will win $2 if you do NOT draw a
Spade?
- –$1/4
- $0
- $1/4
- $2/4
- $3/4
Q30. Whenever the expected
financial value of a bet is greater than $0, you should always take the bet,
regardless of its expected overall value.
- True
- False;
–
Review:
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