CRIM 320 Lecture Notes - Lecture 8: Null Hypothesis, Partial Correlation, Common Cause
Document Summary
X&y analysis line represents correlation between two variables (line of best fit) Correlation correlation is used to measure the degree of association between two interval-level variables. R = symmetrical measure around 0 if r is positive = positive relationship if r is negative = negative relationship. R ranges from -1 to +1 (essentially the same in terms of strength) the closer r gets to 0 the weaker the association is. Positive relationship going in the same direction. Negative relationship moving in opposite directions: measures directionality, do not assume it is (cid:494)bad(cid:495) Null = r=0 if r = 0, there is no relationship: this means that there is no relationship between two variables. A note on causality correlation does not equal causation: use the language association, only measures association there is no specification of dv and iv (like chi-square analysis) All points are matched on plot graph. Know one variable, will know the other variable.