The amounts of time employees of a telecommunications company have worked for the company are normally distributed with a mean of 5.4 years and a standard deviation of 2.1 years. Random samples of size 12 are
Drawn from the population and the mean of each sample is determined.
A)5.4 years, 0.61 years
B)5.4 years, 0.18 years
C)1.56 years, 0.61 years
D)1.56 years, 2.1 years

Question

Quizplus · Accepted Answer

The mean of each sample will still follow a normal distribution with a mean of 5.4 years (the population mean) and a standard deviation of 2.1 years divided by the square root of the sample size (which is 12 in this case). Therefore, the standard deviation of the sample means will be 2.1/sqrt(12) = 0.61 years. This means that choice A is the best answer. The other options either have incorrect means or standard deviations.

The Amounts of Time Employees of a Telecommunications Company Have