Question

The scores of individual students on the American College Testing (ACT) composite college entrance examination have a normal distribution with mean 17.9 and standard deviation 5.8.

(a) What is the probability that a single student randomly chosen from all those taking the test scores 26 or higher?


(b) Now take an SRS of 57 students who took the test. What are the mean and standard deviation of the average (sample mean) score for the 57 students? (Round the standard deviation to 3 decimal places).

μx =

σx =

(c) What is the probability that the mean score x of these 57 students is 19.31 or higher?

Answer 1