A sample of 13 observations is selected from a normal population where the population standard deviation is 8. The sample mean is 41.

a. Determine the standard error of the mean.(Round the final answer to 3 decimal places.)

The standard error of the mean is.

b.Determine the 95% confidence interval for the population mean.(Round thez-value to 2 decimal places. Round the final answers to 3 decimal places.)

The 95% confidence interval for the population mean is betweenand.

c.If you wanted a wider interval, would you increase or decrease the confidence level?

(Click to select)

Decrease

Increase