Two new methods for producing a tire have been proposed. To ascertain which is superior, a tire manufacturer produces a sample of 10 tires using the first method and a sample of 8 using the second. The first set is to be road tested at location A and the second at location B. It is known from past experience that the lifetime of a tire that is road tested at one of these locations is normally distributed with a mean life due to the tire but with a variance due (for the most part) to the location. Specifically, it is known that the lifetimes of tires tested at location A are normal with standard deviation equal to 4,000 kilometers, whereas those tested at location B are normal with σ = 6,000 kilometers. If the manufacturer is interested in testing the hypothesis that there is no appreciable difference in the mean life of tires produced by either method, what conclusion should be drawn at the 5 percent level of significance if the resulting data are as given in Table 8.3?

Transcribed Image Text:

TABLE 8.3 Tire Lives in Units of 100 Kilometers Tires Tested at A Tires Tested at B 61.1 62.2 58.2 56.6 62.3 66.4 64 56.2 59.7 57.4 66.2 58.4 57.8 57.6 61.4 65.4 62.2 63.6