Week 9 Quiz

In the running question's surveys (illustrative), a campus of 12,000 students is the group the claim is about, and each survey asks 400 of those students. Which term names the 12,000 students?

Select one.

• The population, the whole group the claim is about
• The sample, the part of the group that a survey actually reaches and asks
• The random sample, the students chosen by a fair lottery draw from the enrollment list
• The representative sample, the students who resemble the whole campus in every way that matters

Passage (illustrative): "A college is like a store, and in a store the customer is always right, so students should decide their own grades." Which verdict fits the passage?

Select one.

• Not a fallacy, because colleges and stores really do both take payment from the people they serve, week after week
• Hasty generalization, because it rests on what happens in one store and applies it to every college
• Straw man, because it distorts what colleges actually say about how grades are decided and by whom
• Weak analogy, because paying is a real similarity that does not bear on who judges whether work meets a standard

Why is the running question's doorway sample (illustrative), 400 students asked at the library entrance at 11 p.m., a biased sample?

Select one.

• Because 400 students is far too few to say anything useful about a whole campus of 12,000 students
• Because some of the students who said yes at the door were probably not telling the truth
• Because it asked only people already in the library late at night, who are the students most likely to want it open late
• Because the students were asked one at a time at the door rather than all together in one room

Which description fits a random sample, as the course uses the term?

Select one.

• Asking whichever people happen to walk past a busy spot, so that nobody planned who would be asked
• A sample drawn so that every member of the population has the same chance of being picked
• The largest sample a researcher can afford to collect, whatever method is used to gather it
• A sample whose answers come out differently each time the same survey is taken again

In the running question's random sample (illustrative), 400 students were drawn at random from the enrollment list and 240 of them favor overnight hours. What percent of the random sample is in favor?

Select one.

• 75 percent
• 40 percent
• 24 percent
• 60 percent

The running question's doorway sample reads 75 percent in favor and its random sample reads 60 percent, and both samples hold 400 students (illustrative). What explains the difference between the two figures?

Select one.

• The doorway sample was larger, so it caught more of the students in favor of overnight hours
• The method of choosing: the doorway asked only late-night library users, while the random draw gave every student a chance
• Chance alone, since any two samples of the same size will disagree by about that much
• The random sample asked students a different question about the library than the doorway sample did

In 1936 the Literary Digest mailed straw-poll ballots to about 10,000,000 people, got about 2,400,000 back, and predicted a Landon win, yet Roosevelt won in a landslide. Which lesson does the course draw from this real case?

Select one.

• Polls cannot tell us anything reliable about a large population, however their samples are chosen or how many people reply
• The miss came from nonresponse alone, so the telephone and automobile mailing lists were never part of the problem
• How a sample is chosen matters more than its size: a huge sample drawn from tilted lists, or skewed by who replied, can still miss
• A few thousand more mailed-back replies would have been enough to fix the prediction and call the winner

Passage (illustrative): "My cousin caught the flu even though she had a flu shot, so flu shots don't work." Which fallacy does the passage commit?

Select one.

• Hasty generalization
• Weak analogy, because it compares a flu shot with a cousin
• Attack on the person (ad hominem), because it is about the cousin
• Appeal to popularity (ad populum), because many people get flu shots

Argument (illustrative): "300 of 400 doorway students favor overnight hours, so about 75 percent of the campus does." Suppose its premise is true. Which verdict fits the argument?

Select one.

• Valid, because its premise is true and its conclusion follows the numbers in that premise
• Weak, because the sample is biased, even though its premise is true
• Cogent, because its premise is true and it is an inductive argument about the whole campus
• Strong, because 400 students is a large sample for a campus of that size, whoever was asked

A generalization from a well-chosen random sample can be cogent, with a true premise, and still have a false conclusion.

True or false.

• True
• False