Chapter 7, Problem 60SE

Diabetes In a simple random sample of 1200 Americans age 20 and over, the proportion with diabetes was found to be $0.115\left(\text{or }11.5\%\right).$

a. What is the standard error for the estimate of the proportion of all Americans age 20 and over with diabetes?

b. Find the margin of error, using a $95\%$ confidence level, for estimating this proportion.

c. Report the $95\%$ confidence interval for the proportion of all Americans age 20 and over with diabetes.

d. According to the Centers for Disease Control and Prevention, nationally, $10.7\%$ of all Americans age 20 or over have diabetes. Does the confidence interval you found in part c support or refute this claim? Explain.