Given the monthly incomes for 16 randomly selected people with a bachelor's degree in business:
4832.15 5222.36 4917.71 4111.22 3629.96 3749.87 6474.75 5691.48
4646.46 4282.82 2919.35 4752.61 5525.25 4735.39 4019.51 4827.99
a. Find the sample mean
b. Find the sample standard deviation