In the past, the mean lifetime of diesel engine injection pumps has been 12,000 operating hours. A new injection pump is available that is promoted as lasting longer than the old version. In a test of 50 of the new pumps, the lifetimes are as listed in data file XR10113. Based on the sample data, and using the 0.025 level of significance, examine the possibility that the new pumps might have a mean life that is no more than that of the old design. Identify and interpret the p-value for the test.
A computer and statistical software.