In past studies, a fast-food franchise has found the standard deviation of weights for quarter-pound hamburgers to be approximately 0.28 ounces after cooking. A consultant has suggested a new procedure for hamburger preparation and cooking that she believes will reduce the variability in the cooked weight of the hamburgers. In a test of the new method, 61 hamburgers are prepared, cooked, and weighed, with the resulting cooked weights listed in data file XR13062. At the 0.05 level, and assuming a normal distribution for the weights, examine the possibility that the new procedure is actually no better than the old one.
A computer and statistical software.