You are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals.
From a random sample of 69 dates, the mean record high daily temperature in a certain city has a mean of 86.78°F. Assume the population standard deviation is
The 90% confidence interval is
The 95% confidence interval is