Unplugged Practice Test: Logical Reasoning Set 3, Question 9 (Flaw)
Taking the test? Finish it first. This page shows the answer.
- Flaw questions ask you to name the reasoning error the argument commits, not to judge whether its conclusion is true.
- Before you read the choices, describe the argument's error in your own words. Most Flaw questions reward 1 of a small set of recurring patterns, so naming the pattern first keeps the trap answers from sounding right.
- Every question on this test is original, written to the same logical skeletons as real questions, and Steve checked every one himself before release.
The question
Reviewer: Coverage of induction cooktops has badly overstated how often they break down. Across the 25 years from 1994 through 2018, induction cooktops in the city of Marnhill drew fewer than 70 repair claims. Set that against the more than 6,300 repair claims that gas ranges drew in Marnhill during 2018 alone.
9. The reviewer's reasoning is open to criticism because it overlooks
- (A)whether the gas-range claim total in Marnhill was higher in 2018 than in most other years
- (B)whether the number of gas-range claims in Marnhill runs above the number in comparable cities
- (C)whether better installation practices could cut the number of claims against induction cooktops
- (D)how many induction-cooktop claims arose outside Marnhill over those same 25 years
- (E)how many induction cooktops were in service over those 25 years and how many gas ranges in 2018
EWhy (E) is correct
The reviewer concludes cooktop breakdowns are overstated by setting fewer than 70 induction-cooktop repair claims across 25 years in Marnhill against more than 6,300 gas-range claims in Marnhill during 2018 alone. Raw claim counts say nothing about how failure-prone each appliance is without knowing how many of each were actually in service, which is what (E) points to: without those two totals, the comparison can't show induction cooktops break down less often.
Why the other answers are wrong
AWhy (A) is wrong
(A) doesn't touch the gap: even if 2018 were a typical year for gas ranges, the missing count of appliances in service would still leave the comparison broken.
BWhy (B) is wrong
(B) leaves the same problem unanswered: whether Marnhill's gas-range claims outrun other cities says nothing about how many units either appliance had in service.
CWhy (C) is wrong
(C) raises a separate question about fixing induction claims through installation, not about what the reviewer's numbers fail to establish.
DWhy (D) is wrong
(D) would only add more induction claims to one side of the count; it still wouldn't supply the missing totals of units in service.
Common questions
What type of question is this?
Flaw. Flaw questions ask you to name the reasoning error the argument commits, not to judge whether its conclusion is true.
How do I get better at Flaw questions?
Before you read the choices, describe the argument's error in your own words. Most Flaw questions reward 1 of a small set of recurring patterns, so naming the pattern first keeps the trap answers from sounding right. The free LSAT cheat sheet lists the wrong-answer patterns to watch for on every type.
