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Unbiased estimate of population mean

Unbiased estimate of population variance

Let be the population mean time required by an employee to complete a task.

against

at 10% level of significance

Reject if p-value

Test Statistic,

Applying t-test with

From GC, , reject .

Thus, there is sufficient evidence at 10% significance level that there has been a change in the mean time required by an employee to complete the task.