A newspaper article discussed the opening of a Whole Foods Market in the Time-Warner building in New York City. The following data (stored in the file Wholefood 1 ) compared
the prices of some kitchen staples at the new Whole Foods Market and at the Fairway supermarket located about 15 blocks from the Time-Warner building: Source: Data extracted from W. Grimes, "A Pleasure Palace Without the Guilt," The New York Times, February 18, 2004, pp. F1, F5.
a. At the 0.01 level of significance, is there evidence that the mean price is higher at Whole Foods Market than at the Fairway supermarket?
b. Interpret the meaning of the p-value in (a).
c. What assumption is necessary about the population distribution in order to perform the test in (a)?