F I L E A consum er advocate exam ines w h eth er th e lo ngevity o f car b atteries (m ea s u re d in years) is affec te d by t h e b ra n d n am e (factor A ) a nd w h e th e r or n o t th e car is k e p t in a garag e (factor B). In tera ctio n is suspected . Th e results are show n in th e accom panying tab le and are also available on th e te xt website, labeled B r a n d a n d G a r a g e .

Kept in Garage?

Brand Name of Battery 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.

b. At t h e 5 % significance level, is th e re in tera ctio n b e tw e e n bran d n a m e a n d w h e th e r a car is g arag ed?

c. A t th e 5 % significance level, can you conclu de th a t average b attery lives differ by brand name?

d. A t th e 5 % significance level, can you conclude th a t average b attery lives differ d ep e n d in g on w h e th e r a car is garaged?