how do you do longhand

(a) First identify the sample statistic n and the degrees of freedom.

(b) Calculate the confidence interval for the population standard deviation.

A magazine includes a report on the energy costs per year for 32-inch liquid crystal display (LCD) televisions. The article states that 14 randomly selected 32-inch LCD televisions have a sample standard deviation of $3.21. Assume the sample is taken from a normally distributed population. Construct 80% confidence intervals for (@) the population variance of and (b) the population standard deviation G. Interpret the results. (a) The confidence interval for the population variance is (].). (Round to two decimal places as needed.)