Measures of Association

1. Measures of Association 10/30/2012

2. Readings • Chapter 7 Tests of Significance and Measures of Association (Pollock) (pp. 169-179) • Chapter 11 Doing Your Own Political Analysis (Pollock Workbook)

3. Homework • Some Due Today • More Due 11/6 • Chapter 7 Pollock Workbook • Question 1 • A, B, C, D, E, F • Question 2 • A, B, C, D • Question 3 -A, B, C, D • Question 5 • A, B, C, D, E

4. Opportunities to discuss course content

5. Office Hours For the Week • When • Wednesday 11-1 • Thursday 8-12 • And appointment • http://cookpolitical.com/

6. Course Learning Objectives • Students will be able to interpret and explain empirical data. • As this course fulfills the Computational Skills portion of the University degree plan, students will achieve competency in conducting statistical data analysis using the SPSS software program.

7. Why Hypothesis Testing • To determine whether a relationship exists between two variablesand did not arise by chance. (Statistical Significance) • To measure the strength of the relationship between an independent and a dependent variable? (association)

8. Nominal Variables Measures of Association

9. A measure of association is a single number that reflects the strength of the relationship

10. Measures of Association for Nominal Variables

11. Ordinal Variables

12. Measures of association Nominal Ordinal Strength Significance Direction! • Strength • Significance

13. Ordinal Measures of Association

14. Born again

15. Questions • What Percent of Americans believe that Jesus will definitely return in the next 40 years? • State the full directional relationship found in the cross tab. (people who are not born again Christians are….)

17. An Example • Maurice Duverger (1957) wrote that "the simple-majority single-ballot system favors the two-party system" and that "multimember districts favor multiple parties". Hypothesis- PR systems will have more parties • D.V. -enpp3_democ (Effective number of parliamentary parties: 3 cats) • IV-pr_sys (PR system)

18. Another One • From the states.sav • Hypothesis- States that are more secular, will have fewer restrictions on abortion • DV- abortlaw3 • IV- secularism3

19. Open up the States.sav and run and Ordinal Relationship!

20. Exporting outputs

21. Putting Outputs into Word • An Advantage of SPSS is incorporating outputs into documents • The best way to do this is to paste it as an image within your document

22. Copying From SPSS • Right Click on your output and choose copy

23. The “Paste Special Command” • The paste special command gives you the most options • Pasting as an image allows you to resize and move your output around the document Step 1 Step 2

24. What Not to Do • DON’T Just Cut and paste • It is more trouble than it is worth (resizing columns, spacing, etc)

25. Adding a Third Variable How to Control for a Variable?

26. A Third Variable • the relationship between two variables may be spurious, weak or even too strong • "controlling" for a third variable is a method of removing or separating the effects of another variable. • This gets at the underlying relationship

27. Why Add the Third Variable • Is there an antecedent variable at play? • Is the observation different for different groups of people

28. Marijuana and a Third Variable • H1: People with children will have different views on legalization than others of the same ideology • Cross-tabs • Input Row Variable • Input Column Variable • To control for a variable place it in the area that says Layer 1 of 1.

31. Views on Homosexuality, Party ID and Race • DV- homosex2 • IV- partyid3 • Control- race 2