An engineer has measured the hardness scores for a sample of conveyor-belt support bearings that have been hardened by two different methods. The first method is used by her company, and the second method is known to be used by a number of other companies in the industry. With the resulting data in file XR11016, use the 0.05 level of significance in comparing the mean hardness scores of the two samples, and comment on the possibility that the difference between the sample means could have occurred by chance. Identify and interpret the p-value for the test.
A computer and statistical software.