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.
What was Wayne's actual ACT score?
A) 6.6
B) -6.6
C) 11.4
D) 24.6
E) 19.8

Question

Quizplus · Accepted Answer

To find Wayne's actual ACT score, we need to use the formula for standard score:

standard score = (x – mean) / standard deviation

where x is Wayne's actual score, mean is the population mean (18), and standard deviation is the population standard deviation (6).

Substituting the given values, we get:

-1.1 = (x – 18) / 6
-6.6 = x – 18
x = 11.4

Therefore, Wayne's actual ACT score was 11.4. Choice C is the correct answer.

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