POLS 625

Exam 2 Review Sheet

Last Updated: November 5, 2009

 

This review is intended to give you a general idea of what may appear on the exam. The exam will cover material from the assigned readings and material that was presented in the lecture. 

 

I. KKV (Chs 4 and 5)

Ch4 Determining What to Observe

Conditional independence

Homogeneity assumption

Constant effect

Indeterminate research designs

            More inferences than observations

            Multicollinearity

The Limits of random selection

Selection bias

            Selection on the dependent variable (Figure 4.1)

            Selection on an explanatory variable (Figure 4.1)

Intentional selection of observations

            Selecting observations on the explanatory variable

            Selecting a range of values of the dependent variable

            Selecting observations so the key causal variable is constant

            Selecting observations so the dependent variable is constant

 

Ch5 Understanding What to Avoid

Measurement error

            Systematic measurement error

            Nonsystematic measurement error

            Nonsystematic measurement error in the dependent variable (Figure 5.1)

            Nonsystematic measurement error in the independent variable (Fiure 5.2)

Excluding relevant variables: Bias

            Gauging the bias from omitted variables

                        Variable is correlated with the included explanatory variable and has an effect on the dependent variable

Including irrelevant variables: Inefficiency

Endogeneity

           

II. Test of Significance

            One sample case- z (computation)

            One sample case- t (computation, SPSS)

            Chi square test (computation, SPSS)

            t-test for Pearson’s correlation (computation)

 

III. Measures of Association

A. Nominal and ordinal variables

Crosstabs

            Know how to produce a cross-tabulation manually

            Know how to read a cross-tabulation (both bivariate and multivariate)  

            Know how to control for a third variable (Nominal and ordinal variables only)

      Tests of statistical significance and measures of association (SPSS)

            Know how to write a hypothesis

            Know how to test a hypothesis

                        Statistical significance

                        Strength of association

                                    Know how to calculate Lambda manually

                        Direction of association

                        Substantive interpretation

      Bivariate association

                        Lambda, Cramer’s V, Tau b, Tau c (SPSS, interpretation)

      Controlling for a third variable (where the third variable is a nominal or ordinal variable)

                        Lambda, Cramer’s V, Tau b, Tau c (SPSS, interpretation)

B. I/R variables

     Pearson’s r (Computation including testing a hypothesis, Excel, SPSS, interpretation)          

   Bivariate regression (SPSS, interpretation)

   Multiple regression (SPSS, interpretation)

 

The following will be provided.

I. Formulae

Z:

 

t:

 

Chi square:

 

Lambda:

 

Pearson’s r

 

 

II. The z, t, and chi square tables and the following table

 

Measurement Types

Statistics

Two nominal variables

Lambda/Cramer’s V

One nominal one ordinal variables

Cramer’s V

Two ordinal variables

 

Kendall’s tau-b (Square crosstab)

 

Kendall’s tau-c

(Not square)

Gamma

I/R variables

(Pearson’s corr. Coeff)

Regression:

R2