Chapter 8, Problem 8.117ACI

Average housing space per person. Even though Japan is an economic superpower, Japanese workers are in many ways worse off than their U.S. and European counterparts. For example, the estimated average housing space per person (in square feet) is 645 in the United States but only 344 in Japan (Diawa House industry, Co., Japan). Suppose a team of economists and sociologists from the United Nations plans to reestimate the difference in the mean housing space per person for U.S. and Japanese workers. Assume that equal sample sizes will be used for each country and that the standard deviation is 35 square feet for Japan and 80 for the United States. How many people should be sampled in each country to estimate the difference to within 10 square feet with 95% confidence?