Lab 9 (Ch 9 t Statistic) Lab 9 (Ch 9 t Statistic) 6. A researcher conducts a hypothesis test using a sample of n = 20 from an unknown population. 1. For a two-tailed hypothesis test with a = .05 and a sample of n = 25 scores, the boundaries for What is the df value for the t statistic? the critical region are t = 12.060. a. 19 a. True b. 20 b. False c. 21 d. Cannot be determined from the information given 2. For a one-tailed test with a = .05 and a sample of n = 9, the critical value for the t statistic is t = 1.860 7. A sample of n = 25 scores produces a t statistic of t = 2.062. If the researcher is using a two- a. True tailed test, which of the following is the correct statistical decision? b . False a. The researcher can reject the null hypothesis with a = .05 but not with a =.01. b. The researcher can reject the null hypothesis with either a = .05 or a = .01. 3. A sample of n = 9 scores has a variance of s = 36. What is the estimated standard error for the c. The researcher must fail to reject the null hypothesis with either a = .05 or a =.01. sample mean? d. It is impossible to make a decision about Ho without more information. b. 2 8. A sample is selected from a population with u = 46, and a treatment is administered to the C. 4 sample. After treatment, the sample mean is M= 48 with a sample variance of s = 16. Based on d. 16 this information, what is the value of Cohen's d? a. d = 0.125 b. d = 0.25 c. d = 0.50 4. With a = .05 and df= 8, the critical values for a two-tailed t test are t = +2.306. Assuming all d. Cohen's d cannot be computed without knowing the sample size. other factors are held constant, if the of value were increased to df = 20, what would happen to 9. Which of the following samples will have the smallest value for the estimated standard error? the critical values for t? a. They would increase in magnitude (move farther from zero). a. n = 4 with $2 = 16 b. They would decrease in magnitude (move closer to zero). b. n = 4 with $2 = 64 c . They would not change . C. n = 16 with $2 = 16 d. Impossible to determine without more information d. n = 16 with $2 = 64 5. A sample of n = 25 scores has a mean of M = 40 and a standard deviation of s = 10. What is the estimated standard error for the sample mean? 10. With a = .05, what is the critical t value for a one-tailed test with n = 15? a. 4 a. t = 1.761 b. 2 b. t = 1.753 c. 2.5 c. t = 2.145 1. 1 d. t = 2.131