38. Roper ASW conducted a survey to learn about American adults’ attitudes toward money and happiness (Money, October 2003). Fifty-six percent of the respondents said they balance their checkbook at least once a month.

a. Suppose a sample of 400 American adults were taken. Show the sampling distribution of the proportion of adults who balance their checkbook at least once a month.

b. What is the probability that the sample proportion will be within .02 of the population proportion?

c. What is the probability that the sample proportion will be within .04 of the population proportion?