A simple random sample of 60 items resulted in a sample mean of 80. the population standard deviation is σ = 15. a. compute the 95% confidence interval for the population mean (to 1 decimal). ( , ) b

A simple random sample of 60 items resulted in a sample mean of 80. the population standard deviation is σ = 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?