Can someone explain June 2003 PrepTest #40 Section 3 LR #25

[Kantian]

it's about north american PHD program, and DOES NOT WEAKEN problem.

I can see why B is correct, because age of applicants has little to do with the decline, but I am also not sure about E, which states applicants outside north America has declined.

[LSAT All Star]

it's about north american PHD program, and DOES NOT WEAKEN problem.

I can see why B is correct, because age of applicants has little to do with the decline, but I am also not sure about E, which states applicants outside north America has declined.

You always have to watch out for this catch.  The argument is talking about numbers while Choice E is talking about percentages.  If raw numbers had declined (like the argument states) and the percentage from outside North America has declined, it could be true that the percent from within North America is up (which would mean interest within North America has not declined). 

BTW, this is question 26

[Bernie]

It's a causal argument.

The mystery is that there has been a decline in the number of applicants for admission to PHD art history programs.  The author concludes that the cause must be less interest among recent North American college students in choosing an art history career.

Each of the wrong answers weakens by giving an alternative cause.  Choice A suggests that the decline is actually due to a lack of reporting. Choice C suggests that the decline is due to data error.  Choice D suggests that the decline could be due to the students simply beginning their art history careers without a PhD. 

Likewise, choice E suggests that the reason for the decline is due to a drop in the interest among non-North Americans (notice that the conclusion specifically blames North American college graduates.)

[Kantian]

It's a causal argument.

The mystery is that there has been a decline in the number of applicants for admission to PHD art history programs.  The author concludes that the cause must be less interest among recent North American college students in choosing an art history career.

Each of the wrong answers weakens by giving an alternative cause.  Choice A suggests that the decline is actually due to a lack of reporting. Choice C suggests that the decline is due to data error.  Choice D suggests that the decline could be due to the students simply beginning their art history careers without a PhD. 

Likewise, choice E suggests that the reason for the decline is due to a drop in the interest among non-North Americans (notice that the conclusion specifically blames North American college graduates.)

But choice E is not relevent no? its giving an alternate explanation not relevant to the author's conclusion, so i dont see how it weakens it

[LSAT All Star]

By definition, an alternative explanation weakens an argument, no?

Direct relevance to the conclusion is not the only possibility for an alternate explanation.  In this case, Choice E provides an alternate explanation of the data.  (Although this really is directly relevant to the conclusion).