A random sample of n = 16 scores is selected from a normal population with a mean of μ = 50. After a treatment is administered to the individuals in the sample, the sample mean is found to be M = 54. If the population standard deviation is σ = 8, is the sample mean sufficient to conclude that the treatment has a significant effect? Use a two-tailed test with α = .05. (Hint: Recall that the critical value for a two-tailed test with α = .05 is z < –1.96 or z > 1.96.) With σ = 8, z =    . You  ___   conclude that the treatment has a significant effect. If the population standard deviation is σ = 12, is the sample mean sufficient to conclude that the treatment has a significant effect? Use a two-tailed test with α = .05. With σ = 12, z =    . You  ____  conclude that the treatment has a significant effect.   Comparing your answers for the two cases you just tested, explain how the magnitude of the standard deviation influences the outcome of a hypothesis test. A larger standard deviation ____the likelihood of rejecting the null hypothesis.