One sample is selected to represent scores in treatment 1 and a second sample is used to represent scores in treatment 2. Which set of sample statistics would present the clearest picture of a real difference between the two treatments?
a. M1 = 36, M2 = 40, and both variances = 43
b. M1 = 36, M2 = 40, and both variances = 6
c. M1 = 38, M2 = 40, and both variances = 43
d. M1 = 38, M2 = 40, and both variances = 6