A sample of 245 observations is selected from a normal population for which the population standard deviation is known to be 25. The sample mean is 20.
(a) Determine the standard error of the mean. (Round your answer to 3 decimal places.)
Standard error of the mean
(c) Determine the 90% confidence interval for the population mean. (Round your answers to 3 decimal places.)
Confidence interval of ___________ and _______________________