Q9 - In a sample containing 1,000 peanuts

[ohthatpatrick]

Question Type:
Match the Reasoning

Stimulus Breakdown:
Conclusion: Infection with Asper is more common in B than in A.
Evidence: Out of 1000 of each of them, 200 from B had Asper, while only 50 from A had it.

Answer Anticipation:
Seems like a reasonable conclusion: from equal sample sizes, the prevalence of Asper was greater in B than in A. The only potential gap in this reasoning is whether the samples were representative of the overall lots. But we should anticipate a reasonable argument that draws a reasonable conclusion on the basis of two, equal, robust sized samples.

Correct Answer:
D

Answer Choice Analysis:
(A) This is a Part to Whole flaw, which does not match the original.

(B) This has two conditional premises that chain together (A -> B -> C) to yield a conclusion that goes from A -> C. Not a match.

(C) I would immediately suspect that the matching number 1000 is a trap. This argument involves correlation to causality. The original did not.

(D) Yes! This draws a reasonable conclusion on the basis of two equal, robust-sized samples.

(E) This is the same as (B), an A->B->C premise chain that yields an A->C conclusion.

Takeaway/Pattern: The salient feature of the original argument was simply that the evidence involved looking at the results of two large, equal sized samples. The conclusion was only about prevalence. There was no conditional logic (B, E), causality (C), or part v. whole flaw (A).

#officialexplanation

[skapur777]

(D) is the correct answer, but I only ascertained this because the others aren't even close to the same reasoning.

However, it seems to be that the logic in the stimulus is correct. Yet the conclusion doesn't exactly follow in choice (D), the only polled three thousand registered voters, and while 100 more liberals of this sample happened to support him, isn't it getting a little too carried away to assume Pollack has more liberal support than conservatives? am i thinking too globally here?

[farhadshekib]

(D) is the correct answer, but I only ascertained this because the others aren't even close to the same reasoning.

However, it seems to be that the logic in the stimulus is correct. Yet the conclusion doesn't exactly follow in choice (D), the only polled three thousand registered voters, and while 100 more liberals of this sample happened to support him, isn't it getting a little too carried away to assume Pollack has more liberal support than conservatives? am i thinking too globally here?

The stimulus actually has the same pattern of reasoning here.

It presents a sample of 1,000 peanuts in Lot A and 1,000 peanuts in Lot B.

However, the conclusion is about the over-all rate of infection in both Lot B and A respectively.

It's simply making a logical inference based on a supposedly representative sample.

[VickX462]

Question Type:
Match the Reasoning

Here's how I solved this:

The argument is laid out in a pretty simple, straightforward order: premise––premise––conclusion.
Premise 1: 1000 peanuts from lot A and 1000 from lot B; 50 of the peanuts from lot A are found to be infected with Asp.
Premise 2: Two hundred of peanuts from lot B are found to be infected with Asp.
Conclusion: infection is more widespread in lot B than in A

I noticed from the reading that there are 2 premises and the conclusion is a comparison. The premises are not conditionals and the argument compares the two premises with each other.

Let's start with easy elimination using the conclusion and the type and number of the premises:
(A): Only 1 premise and the conclusion not a comparison; eliminate
(B): Premises and the conclusion are in conditional form, eliminate
(C): Conclusion states a causal relationship, not a comparison; eliminate
(D): Looks good. Keep it
(E): There is no comparison throughout the reasoning; eliminate

That's why I selected D as the right answer.

[JinZ551]

so tricky that the lsat writer set the number "300" as "300", and the number 400 is appeared to be "four hundred"

[Laura Damone]

Agreed! Unnecessary roughness added to an already-difficult numbers question!