The number of miles of useful tread wear (in 1000s) was determined for tires of each of...

The number of miles of useful tread wear (in 1000s) was determined for tires of each of five different makes of subcompact car (factor A, with I = 5) in combination with each of four different brands of radial tires (factor B, with J = 4 ), resulting in IJ = 20observations. The values SSA = 30.6, SSB = 44.1 and SSE = 59.2 were then computed. Assume that an additive model is appropriate.

a. Test using a level .05 test.

b. using a level .05 test.