12.  To evaluate the effect of a treatment, a sample of n = 8 is obtained from a population with a mean of u = 40, and the treatment is administered to the individuals in the sample.  After treatment, the sample mean is found to be M = 35. PLEASE SHOW ALL WORK.

a.  If the sample variance is s(2) = 32, are the data sufficient to conclude that the treatment has a significant effect using a two-tailed test with a = .05?

b.  If the sample variance is s(2) = 72,  are the data sufficient to conclude that the treatment has a significant effect using a two-tailed test with a = .05?

c.  Comparing your answer for parts a and b, how does the variability of the scores in the sample influence the outcome of a hypothesis test?