7.- Suppose that a 1973 economic study involved a simple random sample of 36 U.S. millionaires whose mean age was 58.53 years with a sample standard deviation of 13.36 years. a) Obtain a 95% confidence interval for .

b) Obtain a 90% confidence interval for .

c) According to records from 20 years ago, the value of is 63.33 years. Do you find evidence to reject this null hypothesis and accept Ha: 63.33? Answer: YES NO because:

i) The test statistic value is (inside) (outside) the Rejection Region. ii) The p-value is:

d) According to records from 20 years ago, the value of is 12 years. Do you find evidence to reject this null hypothesis and accept Ha: 12? Answer: YES NO because: i) The test statistic value is (inside) (outside) the Rejection Region. ii) The p-value is: