please explain your answer well and the formulas you use

36. The capacities (in ampere-hours) of 10 batteries were recorded as follows: 140, 136, 150, 144, 148, 152, 138, 141, 143, 151 (a) Estimate the population variance ? (b) Compute a 99 percent two-sided confidence interval for ?. (c) Compute a value v that enables us to state, with 90 percent confidence, that 2 . ? 2 is less than u