Question

n two separate studies, the actual difference between the means of a treated group and an untreated group is 3 points. However, in one study, the σM1-M2 is very large and so the 3 points is not found to be significant. In the other study, the σM1-M2 is very small and so the 3 points is found to be significant. What might have caused this big difference in the σM1-M2 for the two studies?

Answer 1

It may be due to the sample size. There is a possibility the sample may be too large, which will affect the significance of the outcome.