Explain how the power of a hypothesis test is influenced by each of the following. Assume that…
Explain how the power of a hypothesis test is influenced by each of the following. Assume that all other factors are held constant.
a. Increasing the alpha level from .01 to .05.
b. Changing from a one-tailed test to a two-tailed test.
c. Increasing effect size.
Under what circumstances is a t statistic used instead of a z-score for a hypothesis test?
Suppose that a researcher is interested in whether an exercise improves intelligence. The researcher randomly selects 100 participants, assigns them to an exercise program, and measures intelligence at the end of the exercise program. The measurement of intelligence has a known or assumed average score of m 5=100 and a known or assumed standard deviation of s = 15 in the population.
a. What hypothesis test should the researcher use to evaluate whether the treatment affected intelligence?
b. If s and s2 were unknown, what hypothesis test should be used?