In 2017 Americans spent a record 9.1 Billion on Halloween related purchases (the balance website) Sample data showing the amount in dollars 16 adults spent on Halloween costumes are as follows.

11, 30, 51, 45, 68, 38, 17, 33, 30, 30, 11, 66, 67, 47, 99, 27

a. What is the estimate of the population mean amount adults spend on Halloween costumes?

b. What is the sample standard deviation?

c. Provide a 95% Confidence Interval of the Population Standard Deviation of the amounts adults spend on Halloween Costumes.