A teacher wants to estimate the mean time (in minutes) that students take to go from one classroom to the next classroom. His research assistant uses the sample time of 41 students to report the confidence interval as [7.79, 10.21]. (You may find it useful to reference the t table.)

a. Find the sample mean time used to compute the confidence interval. (Round final answer to nearest whole number.)

b. Determine the confidence level if the sample standard deviation used for the interval is 2.865. (Round final answer to nearest whole number.)