A researcher estimated an unknown population standard deviation to be 150.Using a sample of size n = 135,the sample standard deviation was found to be 100.The researcher now wishes to establish a 95% confidence interval for the population mean.Which of the following is the correct standard error of the mean to use in calculating the desired confidence interval?
A)Can't be determined from the information given.
B)1.05
C)12.91
D)0.86
E)8.61

Question

Quizplus · Accepted Answer

The formula for the standard error of the mean is:

SE = s/√n

Where s is the sample standard deviation and n is the sample size.

Plugging in the values given:

SE = 100/√135 ≈ 8.61

Therefore, the correct standard error of the mean to use in calculating the desired confidence interval is 8.61.

A Researcher Estimated an Unknown Population Standard Deviation to Be