Question: A research study comparing three treatment conditions produced means of M₁ = 2, M₂ = 4, M₃ = 6.

a. Compute the variance for the set of three means. (Treat the means as a sample of n = 3 values and compute the sample variance)

b. Now we will change the third mean from M₃ = 6 to M₃ = 15. Notice that we have substantially increased the differences among the three means. Compute the variance for the new set of n=3 means. You should find that the variance is much larger than the value
obtained in part a. Note: The variance provides a measure of the size of the mean differences.