a. A statistics practitioner took a random sample of size 56. The sample mean and standard deviation are 70 and 12, respectively. b. Determine the 95% confidence interval estimate of the population...

a. A statistics practitioner took a random sample of size 56. The sample mean and standard deviation are 70 and 12, respectively. b. Determine the 95% confidence interval estimate of the population mean. c. Repeat part (a) changing the sample mean to 30. d. Describe what happens to the width of the interval when the sample mean decreases.