ACT scores. The scores of students on the ACT college entrance examination in a recent year had a Normal distribution. with mean = 18.6 and a standard deviation of = 5.9.

A.) What is the probability that a single student is randomly chosen from all those taking the test scores 21 or higher?

B.) Now take a simple random sample of 50 students who took the test. What are the mean and standard deviation of the sample mean score x of these 50 students?

C.)What is the probability that the mean score of these students is 21 or higher?