#25 - At Morris University this semester, most of the

[sgd2114]

Hi,

I was down to (D) and (E) and due to time I simply chose (E). After reviewing again I understand how (D) parallels the stimulus well, but I can't get to why (E) is wrong.

For (E): Most of the houses for sale are on the website and most of the condos are not on the website (because fewer than half are). Then (E) concludes that there are more houses than condominiums for sale. This seems to me to match the numbers / percent flaw we see in the stimulus. Is it because, more abstractly, the relationship between houses / condos and Acme Realty doesn't match the student majors / class enrollment relationship quite like the co-op / organic relationship does?

Thank you in advance!

[Adam Tyson]

You're right on about the numbers issues here, sgd2114, but the problem with answer E is that it goes off in a different direction than the stimulus did. If E was to parallel the stimulus, we would conclude that there are more photos of houses than of condos on the website. It's not a question of how many are for sale, but of how many are on the website, just as the stimulus is not about how many students are in each major but about how many students in each major are in the class.

No question about it, answer E is flawed, and it is at least partially a flaw of numbers, but it doesn't match the stimulus as well as D does. Try an abstraction to see why:

Stimulus: Most Xs are in Group A, most Ys are not in Group A, so there must be more Xs than Ys in Group A

Answer E: Most Xs are in Group A, most Ys are not in Group A, so there must be more Xs than Ys in existence

I hope that picture says a thousand words for you!

[sgd2114]

Very clear, thank you!

[caseyh123]

Can you walk through answer d?
I got confused because i thought it sort of reversed the number of entities. Like in the stimulus, we have members of 2 entities (psych and soc majors) going in to 1 group (the class). In answer d, it seems to me that we have one entity (organic) going in to 2 groups (supermarket a or b). Does that make sense? These questions are very confusing for me

[Frank Peter]

Hi Casey,

I like to deal with these sort of questions by putting real numbers to them. Usually I try to make the numbers a bit extreme so the difference are clear. First lets put some numbers to the stimulus fact patterns:

Psychology Majors:
-500 total
-25 taking Intro to Psychology

Sociology Majors:
-10 total
-8 taking intro to Psychology.

So here, we can see how the reasoning that there must be more Sociology majors than Psychology majors taking intro to Psych falls apart. If the composition of one group is very small (here, there are only 10 Sociology majors), then "most" of them could also be a very small number.

Now let's put some numbers to answer choice (D):

Valley:
-10 vegetables total
-8 organic

Jumbo:
-500 vegetables total
-25 organic

Again, same problem. In this example, I have given Valley a comically small number of total vegetables vs. Jumbo. And again, we can see that "most" doesn't mean a whole lot if there is a great disparity between the groups that they are coming from (the total number of vegetables)

[dimi.wassef@yahoo.com]

Can someone help me understand why C is wrong?

[Adam Tyson]

Sure thing, Dimi! In answer C we are not comparing two different groups and talking about most of one and most of the other. It's just for one group - the trees in the arboretum - that we know about "most" (most are local rather than exotic). But our stimulus compared two different groups whose relative sizes were unknown - sociology majors and psychology majors. Without that comparison of two groups, this answer cannot parallel that argument! That's focusing on the structure of the argument, how it's built underneath all the details, which is one of the things you always want to match in your parallel reasoning answers.