QSR magazine reports on the largest quick-serve and fast-casual brands in the United States. The file FastFoodChain contains the food segment (burger, chicken, sandwich, or pizza/pasta) and U.S. mean sales per unit ($thousands) for each of 37 quick-service brands.

a. At the 0.05 level of significance, is there evidence of a difference in the median U.S. average sales per unit ($thousands) among the food segments?

b. Compare the results of (a) with those of Problem 11.11 (a) on page 413.