d. the degrees of freedom 9. A researcher calculates a mean from a sample of 27 people. The following hypotheses are stated: H : m = 40 and H,: m 1 40. For a = .05, what is an appropriate critical value for his statistic? a. 2.021 b. 2.056 C. 1.697 d. 1.684 10. Are more than 80% of inmates substance abusers? In a random sample of 100 inmates, 87 said they were substance abusers. What is the z score? a. 1.50 b. 1.75 c. 2.00 d. 2.75