Scores on the American College Testing (ACT) college entrance exam follow the Normal distribution with mean 18 and standard deviation 6. Wayne's standard score on the ACT was -1.1.
Wayne's buddy Garth took the SAT. His standard score on the SAT was 0.6. This means that Garth's actual score was
A) more than 1 standard deviation below the mean SAT score.
B) less than 1 standard deviation below the mean SAT score.
C) less than 1 standard deviation above the mean SAT score.
D) more than 1 standard deviation above the mean SAT score.
E) Can't tell without knowing the standard deviation.

Question

Quizplus · Accepted Answer

Since Garth's standard score on the SAT was 0.6, we know that his actual score was 0.6 standard deviations above the mean SAT score. The mean SAT score is not given, but since the normal distribution is symmetrical, we know that the answer must be "less than 1 standard deviation above the mean SAT score" since 0.6 is less than 1 standard deviation above the mean in any normal distribution. Therefore, the answer is C.

Scores on the American College Testing (ACT) College Entrance Exam