please answer the second , construct a 99% confidence interval for the population standard deviation o at Bank B

The values listed below are waiting times (in minutes) of customers at two different banks. At Bank A, customers enter a single waiting line that feeds three teller windows. At Bank B, customers may enter any one of three different lines that have formed at three teller windows. Answer the following questions. Bank A 6.4 6.6 6.7 6.8 7.1 7.3 7.5 7.8 7.8 7.8 Bank B 4.2 5.4 5.7 6.3 6.7 7.6 7.6 8.5 9.4 10.0 Click the icon to view the table of Chi-Square critical values. Construct a 99% confidence interval for the population standard deviation o at Bank A. 0.33 min