A sample of 24 observations is selected from a normal population. The sample standard deviation is 23.50, and the sample mean is 57. a. Determine the standard error of the mean. (Round the final answer to 4 decimal places.) The standard error of the mean is .

Determine the 80% confidence interval for the population mean. (Round the final answers to 2 decimal places.)

The 80% confidence interval for the population mean is between and .