In a sample containing 1,000 peanuts from lot A and 1,000 peanuts from lot B, 50 of the peanuts from lot A were found...

Ravi on January 20, 2019

@alymathieu,

Happy to help!

We're told that there are two samples of 1,000 peanuts—one from lot A
and one from lot B. We're then told that 50 of the peanuts from lot A
had an infection with Aspergillus, while 200 peanuts from lot B had
the infection.

The argument then concludes that Aspergillus is more widespread in lot
B than in lot A.

This is a poor argument, but what is it doing? It's comparing the
samples of two things and concluding something based on the sample.

A B

1000 sample 1000 sample
50 A. 200 A.

Therefore, B has more A. in all of it


The question stem asks us to choose the answer that's most similar to
the reasoning in the stimulus.

(A) is incorrect because there is no comparison being made between the
samples of two things. This answer is solely discussing the aspects of
one thing. We can eliminate this.

(B) is incorrect because it's not comparing two things and making a
conclusion based on the comparison. (B)'s structure if A-likely-B and
B-likely-B, therefore A-likely-C. This doesn't match.

(C) is incorrect because it's a causal argument, and it's not making a
conclusion based on the samples of two things. In (C), it is saying
that before the experiments, there was coffee rust, but in the last
1,000 experiments when the fungicide was applied, the coffee rust
infection went away. It concludes that the fungicide's application
caused the coffee rust to disappear. This argument is decent, but its
structure is far different from the structure of the stimulus we
identified above.

(D) is correct; it has identical structure to the structure found in
the stimulus. (D) has samples from two groups, 1,500 from the Liberal
party and 1,500 from the Conservative party, and says that 400
Liberals and 300 of the Conservatives favored Pollack. This is
analogous to 50 peanuts from Lot A and 200 peanuts from Lot B being
infected with Aspergillus from the sample sizes of 1,000 peanuts from
Lot A and 1,000 peanuts from Lot B. (D) then concludes that Pollack
has more support among Liberals than among conservatives, which
perfectly mirrors the conclusion of the stimulus when it says that
infection with Aspergillus is more widespread in Lot B than in Lot A.
This is a great match, and it's our choice.

Liberal party Conservative party
1,500 sample 1,500 sample
400 like Pollack 300 like Pollack

Therefore, the Liberal party has more support for Pollack in all of it

(E) is incorrect because its structure is A - >B - >B, therefore A - >C.
This structure is far different from the one we found in the stimulus,
and there's no conclusion made from the analysis of two samples.

Does this make sense? Let us know if you have any more questions!