A researcher expects a treatment to increase the scores for individuals in a population. The treatment is evaluated using a one-tailed hypothesis test, and the test produces z = +2.40 . Based on this result, what is the correct statistical decision?
a. The researcher should reject the null hypothesis with = .05 but not with = .01.
b. The researcher should reject the null hypothesis with either = .05 or = .01.
c. The researcher should fail to reject H0 with either = .05 or = .01.
d. Cannot answer without additional information
Question 2A researcher conducts a hypothesis test to evaluate the effect of a treatment that is expected to increase scores. The hypothesis test produces a z-score of z = 2.27 . If the researcher is using a one-tailed test, what is the correct statistical decision?
a. Reject the null hypothesis with = .05 but not with = .01.
b. Reject the null hypothesis with either = .05 or = .01.
c. Fail to reject the null hypothesis with either = .05 or = .01.
d. Cannot answer without additional information
Question 3A researcher is conducting an experiment to evaluate a treatment that is expected to increase the scores for individuals in a population that is known to have a mean of = 80 . The results will be examined using a one-tailed hypothesis test. Which of the following is the correct statement of the null hypothesis?
a. > 80 c. < 80
b. > 80 d. < 80
Question 4A researcher administers a treatment to a sample of participants selected from a population with = 80 . If the researcher obtains a sample mean of M = 88, which combination of factors is most likely to result in rejecting the null hypothesis?
a. = 5 and n = 25 c. = 10 and n = 25
b. = 5 and n = 50 d. = 10 and n = 50