A simple random sample of 60 items resulted in a sample mean of 71. The population standard deviation is 15. Compute the 95% confidence interval for...

A simple random sample of 60 items resulted in a sample mean of 71. The population standard deviation is 15.

a. Compute the 95% confidence interval for the population mean (to 1 decimal).

(  ,   )

b. Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean (to 2 decimals).

(  ,   )

c. What is the effect of a larger sample size on the margin of error?

Select

It increases

It decreases

It stays the same

It cannot be determined from the given data

Item 5