Cross tabs and Chi square test with SPSS

Cross tabs and Chi square test with SPSS Dr. Samira M. Mahboub Ph. D Public Health, Alexandria University M. P. H. Public Health, Alexandria University M. B. Ch. B, Faculty of Medicine, Alexandria University FHEA, Higher Education Academy, UK

• The chi-square test for independence, also called Pearson's chisquare test or the chi-square test of association, is used to discover if there is a relationship between two categorical variables.

Assumptions • Assumption #1: Your two variables should be measured at an ordinal or nominal level (i. e. , categorical data). • Assumption #2: Your two variable should consist of two or more responces

Example independent variables that meet this criterion • gender (2 groups: Males and Females), • ethnicity (e. g. , 4 groups: Caucasian, African American and Hispanic), • physical activity level (e. g. , 4 groups: sedentary, low, moderate and high), • profession (e. g. , 5 groups: surgeon, doctor, nurse, dentist, therapist)

The CROSSTABS Procedure • Analyze Menu: • Descriptive Statistics… • Crosstabs • CROSSTABS displays the intersection of values of two or more variables • Highlight variables to create tables, click the arrow to add to Row, Column, then click OK

• Statistics, Cells and Format options are available

Crosstabs Output 1. Table title 2. Column variables 3. Row variables 4. Cell counts (# of cases) 5. Column percents (% of cases in column) 6. Statistics

• If this value 20% or less read the pearson Chi Square value and sig • If more than 20% read likelihood Ratio

• In 2*2 tables read the fisher’s exact test sig

Phi and Cramer’s • Indicate the strength of association • Only look at it if sig results for association in Chi Square test • Phi for 2*2 Tables • Cramer’s for other tables

• Strength of the association might be strong or week • = 0. 1 light • ˃0. 1 to 0. 3 middle • 0. 3 to 0. 5 strong • > 0. 5 very strong

Watch it • https: //www. youtube. com/watch? v=wf. If. EWMJY 3 s • https: //www. youtube. com/watch? v=t 7 FMony. Sj. DY

3 way cross tab • You may also wish to add a control variable in cross tab like gender • For more advanced information watch this • https: //www. youtube. com/watch? v=LUu. LGLGI 650

e. g. we make a 3 way cross tab to compare eye strain among (empoloyee vs staff members) in 2 colleges

For CAMS For Olysha