A random sample of n = 36 scores is selected from the normal population with mean of u = 60. After a treatment is administered to individuals in sample, the sample mean is found to be M = 52.
a. If population standard deviation is o = 18, is the sample mean sufficient to conclude that treatment has significant effect? Employ a two-tailed test with a = .05.
b. If population standard deviation is o = 30, is the sample mean sufficient to conclude that treatment has significant effect? Employ a two-tailed test with a = .05.
c. Comparing your answers for parts a and b, discuss how the magnitude of the standard deviation influences the outcome of a hypothesis test.