A simple random sample of 60 items resulted in a sample mean of 84. The population standard deviation is 12. 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 84. The population standard deviation is 12.

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).

(  ,  )