Chapter 12.1, Problem 77E

In each of Exercises 12.75–12.78, use the one-proportion plus-four z-interval procedure to find the required confidence interval. Interpret your results.

12.77 Breast-Feeding. In a New York Times article “More Mothers Breast-Feed, in First Months at Least,” G. Harris reported that 77% of new mothers breast-feed their infants at least briefly, the highest rate seen in the United States in more than a decade. His report was based on data for 434 infants from the National Health and Nutrition Examination Survey, which involved in-person interviews and physical examinations. Find a 90% confidence interval for the percentage of all new mothers who breast-feed their infants at least briefly.