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- Sat Jun 03, 2017 11:17 am
#35653
Complete Question Explanation
Question #9: Parallel Reasoning. The correct answer choice is (D)
This stimulus obviously deals with one of the possible limitations on survey research. It is widely
understood that sample size affects surveys (trying to determine which presidential candidate
is most popular by asking the first five people you meet is obviously a very small sample). If a
sample is sufficiently large, it is likely that the characteristics of the sample generally match those
of the population from which it was drawn. One thousand peanuts seems to be a large sample size,
and although we do not know how the sample was selected, it is likely that the infection rate for
Aspergillus in the sample would be representative of the rate for the entire lot. Thus, the stimulus
correctly infers lot infection rates from a large, presumably representative, sample. The correct
answer choice will do the same.
Answer choice (A): This reasoning does not contain sampling at all. Inspecting each piece and
then drawing an inference about the resulting machine does not involve sample and overlooks that
possibility of introducing flaws during the assembly process.
Answer choice (B): This is straightforward conditional reasoning and does not involve sampling. It
is, incidentally, valid reasoning and represents a simple additive inference.
Answer choice (C): This is cause and effect reasoning. The purported cause (experimental fungicide)
is shown to have the purported effect (removing the coffee rust infection) in 1,000 experiments. The
answer choice also establishes that the effect never occurs without the cause and draws a logically
supported causal conclusion from the series of experiments. However, the experiments cannot be
considered a sample of some larger population.
Answer choice (D): This is the correct answer choice. In this answer, the researchers survey a
sample of Liberal voters and Conservative votes. Although we do not know if the sample is randomly
constructed and representative, it is large enough (1,500 members of each party) to have reasonable
statistical validity. The author concludes from the sample results that the populations have similar
characteristics (i.e., more support for Pollack among Liberals than among Conservatives). This is the
same pattern of reasoning used in the stimulus.
Answer choice (E): This is also conditional reasoning and is quite similar to answer choice (B). The
argument may be represented as follows: If “my livestock,” then “registered.” If “registered,” then
“not free-range.” Therefore, if “my livestock,” then “not free-range.” Again, this answer does not
contain sampling and is not correct.
Question #9: Parallel Reasoning. The correct answer choice is (D)
This stimulus obviously deals with one of the possible limitations on survey research. It is widely
understood that sample size affects surveys (trying to determine which presidential candidate
is most popular by asking the first five people you meet is obviously a very small sample). If a
sample is sufficiently large, it is likely that the characteristics of the sample generally match those
of the population from which it was drawn. One thousand peanuts seems to be a large sample size,
and although we do not know how the sample was selected, it is likely that the infection rate for
Aspergillus in the sample would be representative of the rate for the entire lot. Thus, the stimulus
correctly infers lot infection rates from a large, presumably representative, sample. The correct
answer choice will do the same.
Answer choice (A): This reasoning does not contain sampling at all. Inspecting each piece and
then drawing an inference about the resulting machine does not involve sample and overlooks that
possibility of introducing flaws during the assembly process.
Answer choice (B): This is straightforward conditional reasoning and does not involve sampling. It
is, incidentally, valid reasoning and represents a simple additive inference.
Answer choice (C): This is cause and effect reasoning. The purported cause (experimental fungicide)
is shown to have the purported effect (removing the coffee rust infection) in 1,000 experiments. The
answer choice also establishes that the effect never occurs without the cause and draws a logically
supported causal conclusion from the series of experiments. However, the experiments cannot be
considered a sample of some larger population.
Answer choice (D): This is the correct answer choice. In this answer, the researchers survey a
sample of Liberal voters and Conservative votes. Although we do not know if the sample is randomly
constructed and representative, it is large enough (1,500 members of each party) to have reasonable
statistical validity. The author concludes from the sample results that the populations have similar
characteristics (i.e., more support for Pollack among Liberals than among Conservatives). This is the
same pattern of reasoning used in the stimulus.
Answer choice (E): This is also conditional reasoning and is quite similar to answer choice (B). The
argument may be represented as follows: If “my livestock,” then “registered.” If “registered,” then
“not free-range.” Therefore, if “my livestock,” then “not free-range.” Again, this answer does not
contain sampling and is not correct.