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.

11	72	26	62
36	34	32	41
50	17	13	95
44	35	65	26

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 confidence interval estimate of the population standard deviation for the amount adults spend on a Halloween costume (to decimals). Use Table 11.1.

2. USA Today reports that the average expenditure on Valentine's Day was expected to be $100.89 . Do male and female consumers differ in the amounts they spend? The average expenditure in a sample survey of 60 male consumers was $138.56, and the average expenditure in a sample survey of 37 female consumers was $68.58. Based on past surveys, the standard deviation for male consumers is assumed to be $32, and the standard deviation for female consumers is assumed to be $14. The z value is 2.576.

Round your answers to decimal places.

a.What is the point estimate of the difference between the population mean expenditure for males and the population mean expenditure for females?

b.At confidence, what is the margin of error?

c.Develop a confidence interval for the difference between the two population means. to