10.96 PC users are often victimized by hardware problems. A study revealed that hardware problems reported to manufacturers could not be fixed by one in three owners of personal computers.

Home PC owners fared even worse than those with work PCs, facing longer waits for service and getting even fewer problems resolved. Relatively few owners gave service technicians high marks for having adequate knowledge or for exerting sincere efforts to help solve the problems with the hardware.

Source: PC World, “Which PC Makers Can You Trust?”

Suppose a study is conducted to compare the service provided by manufacturers to both home PC owners and work PC owners. Of 220 home PC owners who had trouble, 98 reported that their problem was not resolved satisfactorily. When the same question was asked of 180 work PC owners who experienced difficulty, 52 reported that the problem was not resolved. Did the home PC owners experience a greater proportion of problems that could not be solved with help from the manufacturer?

Use the 0.05 level of significance and the MINITAB output that follows to answer the question.

a. Solve using the p-value approach.

b. Solve using the classical approach.

Test and CI for Two Proportions Sample X N Sample p 1 98 220 0.445455 2 52 180 0.288889 Difference  p (1)  p (2)

Estimate for difference: 0.156566 Test for difference  0 (vs  0): Z  3.22 P-Value  0.001