You may find these values useful (you can also find these numbers in the z-table of the textbook, OpenIntro Statistics). Notice that z-values below give you the lower tail probability.

• Z0.05 = −1.645

• Z0.95 = 1.645

• Z0.025 = −1.96

• Z0.975 = 1.96

• Z0.005 = −2.58

• Z0.995 = 2.58

Problem 1. Answer True or False to each of the following, and provide justification.

a) If a test is run and p=0.035, then we can reject H0 at the statistical significance level α =0.01.

b) If a 95% CI for the difference in two independent means is (2.1 to 4.5), there is no significant difference in means.

c) If a 95% CI for the mean is (75.3, 80.9), we would always reject H0: µ = 70 in favor of H1: µ ≠ 70 at α = 0.01.

d) It is more difficult to reject a null hypothesis if we use a 10% level of significance compared with a 5% level of significance.

e) The sample size required to detect an effect size of 0.1 is larger than the sample size required to detect an effect size of 0.50 with 90% power and a 5% level of significance level.