You may need to use the appropriateappendix tableortechnologyto answer this question.A simple random sample of90items resulted in a sample mean of60. The population standard deviation is

=15.

(a)Compute the 95% confidence interval for the population mean. (Round your answers to two decimal places.) to

(b)

Assume that the same sample mean was obtained from a sample of180items. Provide a 95% confidence interval for the population mean. (Round your answers to two decimal places.)

(c)

What is the effect of a larger sample size on the interval estimate?

- A larger sample size provides a larger margin of error.

- A larger sample size provides a smaller margin of error.

- A larger sample size does not change the margin of error.