A student team in a business statistics course performed a factorial experiment to investigate the time required for pain-relief tablets to dissolve in a glass of water. The two factors of interest were brand name (Equate, Kroger, or Alka-Seltzer) and water temperature (hot or cold). The experiment consisted of four replicates for each of the six factor combinations. The following data (stored in PainRelief) show the time a tablet took to dissolve (in seconds) for the 24 tablets used in the experiment:

At the 0.05 level of significance,
a. Is there an interaction between brand of pain reliever and water temperature?
b. Is there an effect due to brand?
c. Is there an effect due to water temperature?
d. Plot the mean dissolving time for each brand for each water temperature.
e. Discuss the results of (a) through (d).

BRAND OF PAIN-RELIEF TABLET WATER Equate 85.87 78.69 76.42 74.43 21.53 26.26 24.95 21.52 Kroger Alka-Seltzer Cold Cold Cold Cold Hot Hot Hot Hot 75.98 87.66 85.71 86.31 24.10 25.83 26.32 22.91 100.11 99.65 100.83 94.16 23.80 21.29 20.82 23.21