This is a Flaw/Descriptive Weakening question.
The stimulus says that a club wanted to determine whether it could increase attendance by changing its weekly meeting from Tuesday to another day. So at one Tuesday meeting, the club's president took a survey of all members present, and 95% said they had no difficulty attending on Tuesdays. The club president therefore concluded that the attendance problem was not due to scheduling conflicts.
This is strange. Why did the president survey the members already present at a Tuesday meeting on whether Tuesday is a good day? They already showed up to the meeting, so Tuesday is obviously a convenient day for them. And while you can say that the Tuesday meeting was not an issue for the Tuesday attendees, you cannot draw the same conclusion about all members. This is the big flaw in the argument. The members present on Tuesday are an unrepresentative sample, and they specifically do not represent the people who were not present on Tuesday.
Here is a helpful analogy. Say I am an ice cream shop owner who only sells vanilla ice cream and I want to increase my revenue by possibly changing my flavor to chocolate or strawberry. So I survey all of my customers and 95% say they have no problem with the vanilla flavor. I therefore decide that my revenue problem is not due to the flavoring of the ice cream. What a silly argument, right? I am asking people who are already buying my vanilla ice cream if vanilla flavor is the issue. The customers surveyed are not representative of people who are not yet my customers.
Answer Choice (B) says that the reasoning makes a generalization on the basis of a sample that is likely to be unrepresentative. (B) picks up on the cookie-cutter flaw above. The club president makes a generalization about all members on the basis of an unrepresentative sample, the members who had no problem showing up on Tuesdays.
Answer Choice (A) says that the reasoning draws a conclusion on the basis of circular reasoning. This is not an instance of circular reasoning. Circular reasoning has conclusions and premises that effectively say the same thing, such as “I am the best because no one in the world is better than me.”
If you picked (A), you might have thought that the argument uses circular reasoning because of the repeated use of Tuesday meeting attendance. However, circular reasoning would look something like “the attendance problem is not due to scheduling conflicts because scheduling conflicts do not create attendance problems.” The stimulus instead has distinct premise and conclusion claims.
Answer Choice (C) says that the reasoning treats a generalization that applies to most cases as if it applied without exception. But the conclusion explicitly accounts for possible exclusions because it says the attendance problem was not due primarily to scheduling conflicts. For (C) to be correct, the argument would have to say that since most members of our club said that weekend meetings are okay, weekend meetings are okay for everybody in our club.
Answer Choice (D) says the reasoning draws a conclusion on the basis of premises that contradict one another. The stimulus does draw a conclusion, but there are no premises that contradict one another.
To contradict the first premise, we have to say that a club does not want to figure out if it could increase attendance by changing its weekly meeting. To contradict the next premise, we have to say that at one Tuesday meeting, the club president did not take a survey. To contradict the last premise, we have to say that of those surveyed, 95% said that they did have difficulty with a Tuesday meeting. None of these contradictory statements are present in the stimulus.
Answer Choice (E) is the oldest mistake in the book. It says that the club president’s reasoning is inferring, solely from the claim that a change is not sufficient to solve a problem, that it is not necessary either.
Let's illustrate what the argument would have to look like for (E) to be correct. A club has decided that it wants to double its attendance. It realized that if they move their meetings from Tuesdays to Fridays, their attendance will increase by only 10%. Since this change is not sufficient, it concluded that it is not necessary either.
That’s sufficiency necessity confusion. It’s a flaw because it’s possible that moving the meeting to Friday, while insufficient, is actually necessary. For example, perhaps providing free beer on Fridays will supply the remaining 90% increase. While neither change is independently sufficient, both are necessary.
A small fraction of the classes at Harrison are night classes.
38% of Harrison students take at least one night class.
29% of students living in Westerville take at least one night class.
Over 38% of students living in Pulham take at least one night class.