20. A curious student wanted to determine if there was a difference in the average price of a quarter pound hamburger in the United States and Japan. The student randomly selected 15 McDonald’s restaurants in the United States and 10 McDonald’s restaurants in Japan and recorded the prices of their quarter pound hamburgers. Prices of the quarter pound hamburgers in Japan were converted to U.S. dollars. The data are summarized in the table below.



Calculate a 99 percent confidence interval for the difference in mean price for a quarter pound hamburger in the United States and Japan.