Questions 10-11 are based on the following.
An annually conducted, nationwide survey shows a
continuing marked decline in the use of illegal drugs by
high school seniors over the last three years.

10. Which of the following, if true, casts most doubt on
the relevance of the survey results described above
for drawing conclusions about illegal drug use in the
teen-age population as a whole?
(A) Because of cuts in funding, no survey of illegal
drug use by high school seniors will be
conducted next year.
(B) The decline uncovered in the survey has occurred
despite the decreasing cost of illegal drugs.
(C) Illegal drug use by teen-agers is highest in those
areas of the country where teen-agers are least
likely to stay in high school for their senior year.
(D) Survey participants are more likely now than
they were three years ago to describe as
"heroic" people who were addicted to illegal drugs and have been able to quit.
(E) The proportion of high school seniors who say
that they strongly disapprove of illegal drug
use has declined over the last three years.



11. Which of the following, if true, would provide most
support for concluding from the survey results
described above that the use of illegal drugs by
people below the age of 20 is declining?
(A) Changes in the level of drug use by high school
seniors are seldom matched by changes in the
level of drug use by other people below the
age of 20.
(B) In the past, high school seniors were consis-
tently the population group most likely to use
illegal drugs and most likely to use them
heavily.
(C) The percentage of high school seniors who use
illegal drugs is consistently very similar to the
percentage of all people below the age of 20
who use illegal drugs.
(D) The decline revealed by the surveys is the result
of drug education programs specifically
targeted at those below the age of 20.
(E) The number of those surveyed who admit to
having sold illegal drugs has declined even
faster than has the number who have used
drugs.

C and C
In question 1, disapproving is not the same as using drugs and thus has no bearing on the relevance of the study.
To support C for question 1, let's say that C is true and that most drug users are those who don't stay in school during their senior years, then it is clearly wrong to survey high school seniors and call the survey "representative" of the population under study. Meaning that it's not because the survey result declined that senior teens will have decreased their drug use because most of those teens are out of school anyways.
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Best Regards,

Paul

C and C again.

I found nice discussion on this topic here an-annually-conducted-nationwide-survey-shows-a-continuing-79479.html
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