A small college town has four pizza parlors that make deliveries. A student doing a research paper for her business management class decides to compare how promptly the four parlors deliver. On six randomly chosen nights, she orders a large pepperoni pizza from each establishment, then records the elapsed time until the pizza is delivered to her apartment. Assume that her apartment is approximately the same distance from the four pizza parlors. The following table shows the times (in minutes) for these deliveries.

Tony's Luigi'sAngelo's Kowalski's

20.0 22.1 22.3 23.9

24.0 27.0 26.0 24.1

18.320.2 24.0 25.8

22.0 32.030.1 29.0

20.8 26.028.0 25.0

19.0 24.8 25.8 24.2

Using the 2.5% significance level, test the null hypothesis that the mean delivery time is the same for each of the four pizza parlors.