Q: Studies conducted by the manufacturer of Boston and Vermont asphalt shingles have shown product weight to be a major factor in the customer's perception of quality. Moreover, the weight represented is the amount of raw material being used and is therefore very important to the company from a cost standpoint. The last stage of the assembly line packages the shingles before the packages are placed on wooden pallets. Once a pallet is full (a pallet for most brands holds 16 squares of shingles), it is weighed, and the measurement is recorded. The data file pallet.xls contains the weight (in pounds) from a sample of 368 pallets of Boston shingles and 330 pallets of Vermont shingles.
a.) For the Boston shingles, is there evidence that the mean weight is different from 3,150 pounds?
b.) Interpret the meaning of the p-value in (a.).
c.) For the Vermont shingles, is there evidence that the mean weight is different from 3,700 pounds?
d.) Interpret the meaning of the p-value in (c).
e.) What assumption is needed for (a) and (c).
f.) Evaluate this assumption through a graphical approach. Discuss