According to the Centers for Disease Control and Prevention, 20.6% of the U.S. population smoked in 2008.

In 2014, a random sample of 650 Americans was selected;

108 of whom smoked.

a. Construct a 90% confidence interval to estimate the actual proportion of people who smoked in the United States in 2014.

b. What is the margin of error for this sample?

c. Is there any evidence that this proportion has changed since 2008 based on this sample?

d. Verify your results with PHStat.

AppendixLO1