3.

a. Construct a 95% confidence interval for the proportion of Americans who ate together seven nights a week.

b. Construct a 95% confidence interval for the difference in the proportion of women and men who personally cook at least 4+ meals per week.

c. Construct a 95% confidence interval for the proportion of Americans who eat out at restaurants at least once a week.

When Americans eat out at restaurants, most choose American food; however, tastes for Mexican, Chinese, and Italian food vary from region to region of the United States. In a recent CBS telephone survey,27 it was found that 39% of families ate together 7 nights a week, slightly less than the 46% of families who reported eating together 7 nights a week in an earlier survey by CBS. Most Americans, both men and women, do some of the cooking when meals are cooked at home, as reported in the following table where we compare the number of evening meals personally cooked per week by men and women.

How often Americans eat out at restaurants is largely a function of income. “While most households earning over $50,000 got restaurant food for dinner at least once in the last week, 75% of those earning under $15,000 did not do so at all.”

In spite of all the negative publicity about obesity and high calories associated with burgers and fries, many Americans continue to eat fast food to save time within busy schedules.

Fifty-three percent of families with kids ate fast food at least once last week, compared with 41% of families without kids. Furthermore, 54% of men ate fast food at least once last week, compared with only 37% of women.
The description of the survey methods that gave rise to this data was stated as follows:
“This poll was conducted among a nationwide random sample of 936 adults, interviewed by telephone. The error due to sampling for results based on the entire sample could be plus or minus three percentage points.”

Number of Meals Cooked 3 or Less 4 or More Men Women 76 24 33 67