19. This LSAT resolve conflicting facts passage contains a question stem that requires that "all" data be explained. As such, be wary of answer choices that only explain part of the discrepancies. The information that needs to be resolved :

	X	YET	Y
	80% of both improve first two weeks.		90% of improved recur third week.
	New drug for insomnia.		Same effects as placebo.

 

(A) explains why more than half of those taking the new drug might have a recurrence of insomnia, (A) does not explain why those who took the placebo experienced similar effects.

(B) might explain why the drug and the placebo produced similar results for the first two weeks, but does not explain why those who had reported relief had a recurrence of insomnia in the third week. If more than half ("most") episodes of insomnia are prevented, then 90% of each group would not have reported a recurrence.

(C) might explain why the new drug quit working after three weeks, but does not explain why the placebo produced similar results.

(D) is the correct choice. More than half of insomniacs sleep better in a new environment, and thus the 80% who reported significant relief, and, after the third week, the environment is no longer new, and thus the return of insomnia. Additionally, the new drug has no effect, and thus is the equivalent to a placebo in regards to effect on an insomniac's sleeping ability.

For (E), if at least one ("some") insomniac is unable to reliably determine how much sleep s/he had, then apparently s/he would not have reported significant relief during the first two weeks, and would have been among the 20% who did not report "significant relief". S/he might have simply reported "I don't know." Those who did not report results are not part of the discrepancy.

 

20. This LSAT weaken question requires that you analyze an advertisement.

	P1: Country Classic only car in its class with TrackAid.
	_______________________
	C: If safety-conscious person seeking to buy new car in this class, Country Classic only car for you.

The argument states that Country Classic is the only car in its class with TrackAid, and later describes what TrackAid does. But, the argument never states that TrackAid is the only method that keeps rear wheels from spinning on slippery surfaces. If another car in the same class has a method that keeps rear wheels from spinning on slippery surfaces, then the Advertisement's claim that the Country Classic is the only car in its class for you is misleading, and (D) is the correct choice.

(A) The argument doesn't claim that the Country Classic is the only one with an anti-lock braking system. Instead, it assumes that the Country Classic is the only one in its class with an anti-lock braking system that includes TrackAid.

(B) Just because a company makes one car that includes TrackAid does not necessarily mean that that company's other cars include TrackAid.

(C) states what would happen if a car doesn't have an anti-lock braking system, which is irrelevant because the Country Classic does have an anti-lock braking system.

(E) The cost of the vehicle is irrelevant. The argument is focused on safety only.

 

21. The Sociologist's argument works this way:

	P1: Ignore unpleasant realities and tell small lies g Sincerity
	Sincerity g Ignore unpleasant realities and tell small lies
	P2: Trust g Succeed
	Succeed g Trust
	_______________________
	C: Succeed g Community members must be willing to face unpleasant realities and speak honestly (i.e., Ignore unpleasant realities and tell small lies)

A good way to approach this argument is to recognize the conditional statements. Write those out as above, and the assumption will become easier to spot. Compare the contrapositive of the second premise with the conclusion. The conclusion works this way:

Succeed g Trust g Sincerity g Ignore unpleasant realities and tell small lies

The contrapositive of the second premise: Succeed g Trust . The contrapositive of the first premise: Sincerity g Ignore unpleasant realities and tell small lies. The assumption: Trust g Sincerity, and (A) provides this.

(B) states "more" and "more likely", but the argument deals with absolutes.

(C) states "sometimes can".

(D) provides this:

Ability to be Sincere g Willing to face unpleasant realities

(E) mixes "often" with this:

C: Failure g Community members must be willing to face unpleasant realities and speak honestly

Whereas the contrapositive of the conclusion is this:

C: Community members must be willing to face unpleasant realities and speak honestly g Succeed