(Solved): A simple random sample of 90 items resulted in a sample mean of 60 . The population standard deviat ...

A simple random sample of 90 items resulted in a sample mean of 60 . The population standard deviation is $?=15$. The $95\%$ confidence interval for the population mean is from to Assume that the same sample mean was obtained from a sample of 180 items. Now, the $95\%$ confidence interval for the population mean is from to What is the effect of a larger sample size on the interval estimate?