What is the standard deviation of the sampling distribution of sample means for whenever service life is in control?
A)5 hours
B)6.67 hours
C)10 hours
D)11.55 hours
E)20 hours

Question

Quizplus · Accepted Answer

The standard deviation of the sampling distribution of sample means is given by the formula sigma/sqrt(n), where sigma is the population standard deviation and n is the sample size. Since we are told that service life is in control, it means that the population standard deviation is known and equal to 30 hours. If we choose a sample size of n=9 (as stated in the question), then the standard deviation of the sampling distribution of sample means is 30/sqrt(9) = 10 hours. Therefore, the answer is C)10 hours.

What Is the Standard Deviation of the Sampling Distribution of Sample