In 2017, Americans spent a record-high $9.1 billion on Halloween-related purchases (the balance website). Sample data showing the amount, in dollars, 16 adults spent on a Halloween costume are as follows. Hint(s) Che 10 70 25 64 35 33 34 46 50 16 11 99 44 31 65 23 a. What is the estimate of the population mean amount adults spend on a Halloween costume (to 2 decimals)? b. What is the sample standard deviation (to 2 decimals)? c. Provide a 95% confidence interval estimate of the population standard deviation for the amount adults spend on a Halloween costume (to 2 decimals). Use Table 11.1.