Question

1. Over the past year, the vice president for human resources at a large medical center has run a series of three-month workshops aimed at increasing worker motivation and performance. To check the effectiveness of the workshops, she selected a random sample of 35 employees from the personnel files and recorded their most recent annual performance ratings, along with their ratings prior to attending the workshops. If the vice president for human resources wishes to assess the effectiveness of the workshop in improving performance ratings, what sort of test should she use?
   1. Difference in variances – F-Test
   2. Difference between means – Independent Samples (μ₁– μ₂)
   3. Difference between means – Matched Pairs (μ_D)
   4. Difference between proportions (π₁ – π₂)

Answer 1

Here, the vice president for human resources wishes to assess the effectiveness of the workshop in improving performance ratings. She selects a random sample of 35 employees and records their before and after attendingthe workshops. So, the two samples here are from the same 35 employees, i.e, they are dependent. Hence, we must conduct the two sample t test for difference in means for dependent samples, i.e , for matched pairs.

The correct answer is : Difference between means – Matched Pairs (μD)