Q9 - In a recent study, each

[tamwaiman]

I don't like this question at all.

Both (B) and (C) are irrelevant, and (A)(D)(E) make no difference in nature.

Why (C) is relevant? Someone might say that (C) assures the Group B young, but even if all Group Bs are 41 years old, they are still younger than Group A(65-75). Therefore, whether 39 or 41, it is relevant to the conclusion.

Thanks.

[giladedelman]

Thanks for posting! This reminds me of a jazz rehearsal I was in once, as a teenager. I complained that I didn't like the piece we were playing. The director looked at me and said, "You don't need to like it, you need to learn to play it!"

So anyway, here we have a study that looks at two groups: one group of old people, and one group of college students. Only one old person fails to make the phone call at the proper time, compared to fourteen of the college students. Therefore, the argument concludes, at least one type of memory doesn't deteriorate with age.

Of course, there are a whole bunch of assumptions here! First of all, how do we know the college students aren't also ages 65-75? Where I went to college, there were a lot of older people in my history classes -- they were called "lifelong learners."

Also, how do we know the groups were the same size? What if there were only two people in the first group, and a hundred in the second? In that case, 50% of the old people failed, compared to only 14% of the college students. So the size of the groups matters.

And isn't the argument making an assumption about the cause of the lapses? What if other factors prevented the college students from making the phone calls -- maybe they couldn't get to a phone, or maybe they remembered but just didn't care!

Now, the question asks us which of the following is LEAST helpful in establishing that the claim is properly drawn. So there are going to be four answer choices that help, and one that doesn't help.

(B) is the correct answer because, as you say, it's totally irrelevant to the argument. We know that the time of the call was recorded electronically; we don't care who answered the phone.

(A) helps the argument by addressing the number assumption we identified earlier. If the groups are the same size, then we're better able to compare their performance.

(C) helps the argument because it establishes that the college students are in fact younger than the old folks. You're getting turned around here because you're expecting too much of the answer choices. Remember, we're not looking for a necessary assumption -- it doesn't have to be true that they were all under forty. Perhaps they were all 41, and that would be fine. But the fact that they are under forty means they definitely are younger than the other group, which strengthens the argument.

(D) strengthens by ruling out an alternate explanation for the lapses.

(E) addresses an assumption I didn't notice at first: what if the younger people were told a year in advance to make the calls, and the old people were told five minutes in advance? Then we would expect the old people to have a significant advantage. So this answer rules out that possibility, which helps the argument.

Does that clear this one up for you, or are you still annoyed?

[tamwaiman]

Thank you.

Now I know that it is a strengthen question, though younger than 40 is not necessary. It makes sense - younger than 40 is stricter.

And thanks for ""You don't need to like it, you need to learn to play it!", I'll remember it.