7. A key part to understanding this discrepancy is distinguishing yield and total number. Try using a simple graph:

 

		Hybrid	Nonhybrid
	Seeds Planted Per Acre	100	100
	Plants Grown Per Acre	80	50
	Yield Per Acre	80%	50%

 

 

 

 

 

Thus, it's possible that hybrid crops can have a higher yield, yet more total nonhybrid crops are grown. The discrepancy is only about the yield, however, and ensure that you focus on that. Also, for "many" (two or more) real world plantings of the hybrid crops, yields have "not increased", which leaves open the possibility that yields remained constant.

How to resolve the discrepancy? Find a difference between the test conditions and real world conditions that shows the test conditions were better, such as that the test plantings benefited from better conditions, as provided in (C).

(A) does nothing because it refers to total number of crops not yield.

(B) makes things more confusing by stating that what was found in the test world (higher yields for hybrids) was also found in some areas of the real world.

(D) refers to the sale of crops. This might explain why more nonhybrid crops were actually grown, but the discrepancy is about crop yield. Again, distinguish between yield and total crops grown.

For (E), perhaps with subsidies, hybrid farmers chose to be lazy and grow fewer total crops. But, again, this refers to total not yield.

 

8. The question stem includes the words "inferred" and "assumed", so don't glance and guess as to what the question is asking for. Read the question to ensure that you know what it requires -- an assumption. The argument works this way:

 

	P1: This stamp exhibits printing error.
	P2: If stamp in good condition, then most important factors to determine value are rarity and age.
	P3: This stamp in good condition.
	P4: This stamp old.
	A: If printing error, then stamp rare.
	_______________________
	C: This stamp probably highly valuable.

 

The author assumes that a printing error is sufficient for that stamp to be rare, an assumption listed in (B). Try negating (B) by placing "not" before "always". This negation would weaken the argument and thus (B) is a required assumption.

(A) is a guess, but the argument simply states "age" and "quite old". There's no explicit or implicit information that connects increased age to increased value.

(C) states that greater than half of all printing error stamps are in collectors' possession. But, collectors' ownership of stamps has nothing to do with the argument.

(D) is a guess that if rarity and age are the "two most important", then those two are necessarily of equal importance. However, it's possible that the two are the "two most important", but of the two, one is more important than the other. The argument does not provide any information either way, and the argument is not based on the assumption that the two be of equal importance.

(E) states this:

Old, Rare, Poor Condition g Usually Not Valuable

This is a guess as to what the author might believe, based on the second premise, but the argument is focused on stamps that are in good condition, and thus stamps in poor condition are irrelevant.

 

9. The researchers' argument contains two obvious assumptions. First, it assumes that the "several hundred female physicians" are representative of "women". Second, it assumes that correlation equals causation. (A) weakens the argument by showing that another possible cause exists -- the nonvitamin nutrients.

(B) refers to "not in men", but, although the argument focuses on women, this does not necessarily mean that folate and B6 do not have an effect on the development of coronary disease in men.

(C) seems to touch upon the sampling assumption, but the argument is based purely upon physical factors -- diet and its effect on development of coronary disease, whereas (C) refers to the knowledge that physicians have. Also, note the exact conclusion and the argument's scope. The argument does not take an extra step and provide a suggestion or prediction, i.e., it does not advise women to increase their intake of folate and B6, nor does it predict that all or most or any women will now see declines in the development in coronary disease.

(D) attempts to attack the evidence rather than the assumption, a common incorrect choice for LSAT weaken questions. Note that the study is about the tendency to develop coronary disease, not the actuality of developing coronary disease.

(E) attempts to attack a prediction that the argument does not make. However, just as for (C), note the argument's scope.