In order to study consumer preferences for health care reform in the U.S., rescarchers from the University of Michigan surveyed 500 U.S. households (Journal of Consumer Affairs, Winter 1999). Heads of household were asked whether they are in favor of, neutral about.

or opposed to a national health insurance program in which all Americans are covered and costs are paid by tax dollars. The 434 useable responses are summarized in the table below. A STATISTIX printout of the analysis of the data is shown on p. 443.

a. Is there sufficient evidence to conclude that opinions are not evenly divided on the issue of national health insurance? Conduct the appropriate test using a = .01.

b. Construct a 95% confidence interval for the proportion of heads of household in the U.S. population who favor national health insurance.