Recently, Seasons Pizza was receiving customer complaints about erratic pizza delivery times. To address this issue, Seasons made some operational changes in its restaurant and added more delivery people to its staff. To study the effectiveness of these changes, Seasons would like to test the hypothesis that the standard deviation for the delivery times of its pizzas is less than 12 minutes. The following data represent a random sample of delivery times (in minutes). These data can also be found in the Excel file pizza delivery times.xlsx.

23 24 23 36 30 40 34 24 28 29 15 27

17 22 33 30 15 10 12 21 38 35 18 20

a. Using = 0.05, test whether Seasons Pizza's goal was achieved.

b. Verify your results using PHStat.

c. Interpret the p value obtained from the software.