how do you compute the 99%

A random sample of the closing stock prices in dollars for a company in a recent year is listed below. Assume that . is $2.29. Construct the 90% and 99% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. 16.91 21.47 22.98 18.07 15.98 19.03 15.75 20.66 18.61 22.56 22.28 21.67 19.27 18.51 21.39 17.44 The 90% confidence interval is ($ 18.53 ,$ 20.54 ). (Round to two decimal places as needed.) The 99% confidence interval is ($5D) (Round to two decimal places as needed.)