Confidence interval for variance/standard deviation

Please explain steps!

4. Condence interval for vgugg' ncefstgogard deviation: Use the given condence le'vel and sample data to nd a condence interval for the population standard deviation (sigma). Assume that a simple random sample has been selected from a population that has a normal distribution: Starting salaries of coilege graduates who have taken biology course: 95% condence level, 11 --~ 5 1, sample mean = $45,678, sample standard deviation = $9900. :1. Check requirements: 1:. Calculate Critical Values (use Chi-square Distribution): c. ' Find Condence Interval