Statistics SPSS Review Fall 2009 Types of Measures

Statistics & SPSS Review Fall 2009

Types of Measures / Variables • Nominal / categorical – Gender, major, blood type, eye color • Ordinal – Rank-order of favorite films; Likert scales? • Interval / scale – Time, money, age, GPA

Main Analysis Techniques Variable Type Example Commonly-used Statistical Method Nominal by Nominal blood type by gender Chi-square Scale by Nominal GPA by gender t-test GPA by major Analysis of Variance weight by height GPA by SAT Regression Correlation Scale by Scale

Main Analysis Techniques Variable Type Example Commonly-used Statistical Method Nominal by Nominal blood type by gender Chi-square Scale by Nominal GPA by gender t-test GPA by major Analysis of Variance weight by height GPA by SAT Regression Correlation Scale by Scale

SPSS Cross –tab with Chi-Square

SPSS Cross –tab with Chi-Square p <. 05

Main Analysis Techniques Variable Type Example Commonly-used Statistical Method Nominal by Nominal blood type by gender Chi-square Scale by Nominal GPA by gender t-test GPA by major Analysis of Variance weight by height GPA by SAT Regression Correlation Scale by Scale

SPSS t-test Output

SPSS t-test Output 1. Read means 2. Read Levene’s Test 3. Read p value

Analysis of Variance Variable Type Example Commonly-used Statistical Method Nominal by Nominal blood type by gender Chi-square Scale by Nominal GPA by gender t-test GPA by major Analysis of Variance weight by height GPA by SAT Regression Correlation Scale by Scale

SPSS ANOVA output

SPSS ANOVA output p value

Variables & Statistical Tests Variable Type Nominal by nominal Example Blood type by gender Scale by nominal GPA by gender GPA by major Scale by scale Weight by height GPA by SAT Common Stat Method Chi-square T-test Analysis of Variance Regression Correlation

Variance = s 2 = x i - Mean )2 -----------N Standard Deviation = s = variance

e n i l on i s s e Regr 3 7 H 3. 3 W =

Scatterplot: Sentence by G. P. A.

Regression Coefficients Sentence = -3. 5 G. P. A. + 18

Correlation

Correlation: Sentence & G. P. A.

Correlation: Sentence & G. P. A. p value

Correlation Interpreting r as r = -. 22 2 r r 2 =. 05 G. P. A. “explains” 5% of variance in SENTENCE length