A consumer advocate examines whether the longevity of car batteries (measured in years) is affected by the brand name (factor A) and whether or not the car is kept in a garage (factor B). Interaction is suspected. The results are shown in the accompanying table.

……...…………………Brand Name of Battery

Kept in Garage?............A……..….B…….……...C

      Yes………………….7, 8, 8……6, 7, 7……      8, 9, 9

       No…………………..5, 6, 6……4, 5, 4…….   6, 7, 7

a. Use Excel to generate the appropriate ANOVA table at the 5% significance level.

b. At the 5% significance level, is there interaction between the brand name and whether a car is garaged?

c. At the 5% significance level, can you conclude that the average battery lives differ by brand name?

d. At the 5% significance level, can you conclude that the average battery lives differ depending on whether a car is garaged?