An army depot that overhauls ground mobile radar systems is interested in improving its processes. One problem involves troubleshooting a particular component that has a high
Failure rate after it has been repaired and reinstalled in the system. The shop floor
Supervisor believes that having standard work procedures in place will reduce the time
Required for troubleshooting this component. Time (in minutes) required troubleshooting
This component without and with the standard work procedure is recorded for a sample of
19 employees. In order to determine if having a standard work procedure in place reduces
Troubleshooting time, they should use
A) a one-tailed paired t-test.
B) a two-tailed test of two independent means.
C) a one-tailed test of two independent means.
D) a two-tailed paired t-test.
E) a test of two proportions.

Question

Quizplus · Accepted Answer

A one-tailed paired t-test is appropriate because the data involves comparing the times (before and after implementing a standard work procedure) for the same group of employees, indicating paired observations, and the hypothesis specifically looks for a reduction (not just any difference) in time, which suggests a one-tailed test.

An Army Depot That Overhauls Ground Mobile Radar Systems Is