19. The argument works this way:

	P1: Smokers are more likely than nonsmokers to develop heart disease.
	P2: Smokers are more likely than others to drink caffeine beverages.
	_________________________________________
	C: Positive correlation between drinking caffeinated beverages and heart disease.

 

 

 

 

The argument does not consider the comparison between smokers who drink caffeinated beverages and smokers who do not. Perhaps smokers who drink caffeinated beverages never (or are much less likely to) develop heart disease than are those smoker who do not drink caffeinated beverages. (Although drinking caffeinated beverages is still not necessarily a cause.) If so, then the argument's conclusion does not follow. (A) is the correct choice.

(B) states "more important", but the argument simply states that a correlation exists, not that any causality exists. Indeed, the argument states that caffeine is not thought to be a cause.

For (C), it doesn't matter which is more strongly correlated, just whether or not a positive correlation exists at all.

(D) states "caffeine consumption" whereas the argument states "caffeinated beverages". "Caffeine consumption" is broad and includes the consumption of caffeine via other methods, such as via medication.

For (E), the argument is not concerned with causality, only with correlation.

 

20. Treat this as an inference question. The passage content and choices are relatively easy to understand. However, the subtleties among the choices are difficult to spot. Notice that no argument appears in the passage -- the second sentence is not a conclusion. Also, do not guess at the author's conclusion. The author does not conclude that supermarkets should discontinue placing commonly purchased items at the rear of the store.

(A) focuses only on the second sentence. Perhaps making customers walk to the rear is good business, even though customers can be alienated. Notice that just because surveys found that inconvenience is the top reason for disliking supermarkets does not necessarily mean that customers will not shop at them.

For (B) and (D), it's possible that distracting customers is great for business; indeed, the first sentence supports this.

(C) states "fail", which is an extreme statement. It's possible that making customers walking to the back of the store is great for business and that the plan has succeeded in that way, even though customers find it inconvenient.

(E) is the correct choice. Compare "unwelcome" in (E) to "fail" in (C).

 

21. The Doctor assumes that lifestyle changes do not have any unhealthy side effects (or that those side effects are relatively harmless compared to those of medication). (C) is the correct choice. Negate (C) by placing "not" in between "are" and "less".

The argument works this way:

	P1: Blood pressure medication has unhealthy side effects.
	P2: Lifestyle changes just as effective in lowering blood pressure.
	A: Lifestyle changes do not have any unhealthy side effects (and if they do, then those side effects are less unhealthy than the side effects of medication.)
	_________________________________________
	C: Healthier to rely on lifestyle changes to reduce blood pressure.

 

 

 

 

 

 

(A) The Doctor does not state "healthiest", but rather "healthier", and thus an either/or argument does not appear.

(B) mixes up information from the passage, but the author's argument does not require this. Notice that (B) is a conditional statement, and that the sufficient condition of (B) is the author's conclusion.

(D) states "always", but the Doctor's argument is limited to reducing blood pressure. We don't know about other medical conditions. Also, an alternative may still contain unhealthy side effects.

(E) states similar side effects, but the author assumes that this does not occur. Also, (E) states "more effective" but the passage states "just as effectively".