The scores of individual students on the American College Testing (ACT),college readiness assessment,have a Normal distribution with a mean of 18.6 and a standard deviation of 6.0.At Northside High,36 seniors take the test.Assume the scores at this school have the same distribution as national scores.What is the standard deviation of the sampling distribution of the sample mean score for a random sample of 36 students?
A)1.0
B)3.1
C)6.0
D)18.6

Question

Quizplus · Accepted Answer

The standard deviation of the sampling distribution of the sample mean (often called the standard error) is equal to the population standard deviation divided by the square root of the sample size. Here, it is 6.0 / sqrt(36) = 6.0 / 6 = 1.0.

The Scores of Individual Students on the American College Testing