To compare four different brands of tires the following experiment was designed. Beginning with 12 identical cars, 3 cars have tires of one brand installed on them, another 3 have another brand, another 3 have another brand, and the remaining 3 have the remaining brand installed on them. One car from each set drives a long pre-determined path on roads. One car from each set drives a long pre-determined path on gravel. One car from each set drives a long pre-determined path on rough, hilly terrain. After each car has driven its path, the amount of wear on the tires is measured and recorded.

a) Can we infer that there are any differences in the amount of wear depending on the brand of tire?13 marks

Printout # ___________________

: ________________________: ________________________

01

p-value: _____________ Conclusion: Reject0Do not reject0

b) Can we infer that there are any differences in the amount of wear depending

on what terrain is driven (roads, gravel or rough, hilly terrain)?5 marks

p-value: _____________ Conclusion: Reject0Do not reject0