Advanced Statistics Quiz 2

8. A researcher conducts a hypothesis test using a sample from an unknown population. If the t statistic has df=35, how many individuals were in the sample? a. n=34 b. n==35 c. n=36 d. cannot be determined from the information given

c. n=36

10. A sample of n=9 scores has SS=200. What is the variance for this sample? a. 25 b. 5/3 c. 25/9 d. 5

a. 25

9. A researcher conducts a hypothesis test using a sample of n=40 from an unknown population. What is the df value for the t-statistics? a. 39 b. 40 c. 41 d. cannot be determined from the information given

a. 39

With a a= 0.05 what is the critical t value for a one-tailed test with n=25? a. t=1.711 b. t=2.064 c. 2.708 d. 2.060

a. t=1.711

1. A sample of n=25 scores has a mean of M=40 and a variance of s^2=100. What is the estimated standard error for the sample mean? a. 4 b. 2 c. sqrt(2) d. 1

b. 2

A sample of n=4 scores has SS=48. What is the estimated standard error for the sample mean? a. 1 b. 2 c. 4 d. 16

b. 2

A hypothesis test with a sample of n=25 participants produces a t-statistic of t= +2.53. Assuming a one-tailed test with the critical region on the right- hand tail, what is the correct decision? 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. c. the researcher must fail to reject the null hypothesis with either a = .05 or a = .01. d. It is impossible to make a decision about H0 without more information.

b. The researcher can reject the null hypothesis with either a = .05 or a = .01.

7. Which of the following is a fundamental difference between the t-statistic and a z-score? a. The t-statistic uses the sample mean in place of the population mean. b. The t-statistic uses the sample variance in place of the population variance. c. The t-statistic computes the standard error by dividing the standard deviation by n-1 instead of dividing by n. d. all of these are differences between t and z.

b. The t-statistic uses the sample variance in place of the population variance.

A sample size increases a. the value of df also increases b. the t distribution becomes more like a normal distribution c. the critical values of t move closer to zero d. all of the other options are true as sample size increases

d. All the other options are true as sample size increases.

2. A sample has a mean of M=39.5 and a standard deviation of s=4.3, and produces a t statistic of t=2.14. For a two-tailed hypothesis test with a= 0.05, what is the correct statistical decision for this sample. 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. c. the researcher must fail to reject the null hypothesis with either a = .05 or a = .01. d. It is impossible to make a decision about H0 without more information.

d. It is impossible to make a decision about H0 without more information.