Correlation Coefficient Chapter 13 Correlation Coefficient We are now moving from comparing groups on one variable to comparing relationships between two (ore more) variables (left side of path-chart). When to use: When you want to know the likelihood of a relationship or association between two variables. Is there a significant relationship between two variables? (Not causal!!!!!) Here, the relationship between variables and NOT the difference between groups are being examined. Steps: 1. State Null and Research Hypothesis

Null Hypothesis Ho: Ρxy = 0 Research Hypothesis H1: rxy ≠ 0 2. Set risk level (.05, of course) 3. Appropriate test statistic (flow chart) = t Compute test statistic (by hand or computer) Analyze, correlate, bivariate Move two variables to correlated over, click okay

Determine obtained value If by hand, determine df and one or two-tailed (again, one if you have a strong expectation and two otherwise). Here, n is the number of pairs or cases. You subtract by 2 (# of variables rather than groups) with correlation analysis (n-2). Find critical value (SPSS, again, computes significance automatically). (if by hand, Table B4 in Appendix B). 6. Compare and Evaluate Null