PSYCH 100A Lecture 13: Lecture 13-Correlation
Document Summary
Used to measure and describe the relationship between two variables. Variables are observed (as they exist naturally in the environment), not manipulated. Properties: coefficients range between -1 and 1, high correlation strong relationship between x and y, correlation near zero no linear relationship. Characteristics of a relationship: direction of the relationship, positive/negative, form of the relationship, linear/curvelinear, strength of the relationship, perfect/no correlation. Non-monotonic changes direction/horizontal line intersects two points. Measures the degree of and direction of linear relationship between two variables. Is the relationship between food pellets and maze running time in rats significant: h0: = 0, h1: 0. Degrees of freedom: df = n 2 = 10 2 = 8. Look up the two-tailed critical value for df = 8 for = . 05: cv: r = . 632, compare r to. 62% of the variability in maze running time can be explained by the number of food pellets being consumed. (38% left unexplained) .
