Assignment 9: Two Sample Inferences
Due at start of class on 24 March, 2006. Name:

Use SPSS and the standard class data set to answer the following questions. You may want to refer to the original questionnaire. Each question is worth one half a point unless otherwise indicated.

1. Your instructor wants to know if the people in the 10 AM section of this class have a different GPA than the people in the 11 AM section of this class. What type of statistical test should he perform?
1. one sample t-test
2. two sample, between-subjects t-test
3. two sample, within-subjects t-test
2. What is the null hypothesis?
3. What is the alternative hypothesis?
4. Is this a one-tailed or two-tailed test?
1. one-tailed
2. two-tailed
5. What is the α level?

Perform the appropriate statistical test using SPSS. Answer the following questions based on the SPSS output.

6. Which row of the SPSS output should be used?
1. Equal variances assumed
2. Equal variances not assumed
7. What is the value of the t-test?
8. What is the value of degrees of freedom?
9. What is the value of p?
10. What should you conclude?
1. Reject H0
2. Reject H1
3. Fail to reject H0
4. Fail to reject H1
5. Accept H0
6. Accept H1
11. Your instructor wants to know if people who predicted they would earn larger number of points in the class have a different GPA than people who predicted they would earn smaller number of points. "Larger" is defined as the number of points greater than or equal to the median response to the question "There are 640 points available in the class. How many do you expect to earn?" What type of statistical test should he perform?
1. one sample t-test
2. two sample, between-subjects t-test
3. two sample, within-subjects t-test
12. What is the null hypothesis?
13. What is the alternative hypothesis?
14. Is this a one-tailed or two-tailed test?
1. one-tailed
2. two-tailed
15. What is the α level?

Perform the appropriate statistical test using SPSS. Answer the following questions based on the SPSS output.

16. Which row of the SPSS output should be used?
1. Equal variances assumed
2. Equal variances not assumed
17. What is the value of the t-test?
18. What is the value of degrees of freedom?
19. What is the value of p?
20. What should you conclude?
1. Reject H0
2. Reject H1
3. Fail to reject H0
4. Fail to reject H1
5. Accept H0
6. Accept H1

Save ALL of your SPSS output to a file named as your last name. Email me the SPSS output file (the .spo file).

When you are all done with the questions, click on the submit button. Your answers are not submitted unless you click on the button, receive confirmation that your answers have been received, and email your SPSS output to me.