PSYC 2001 Lecture Notes - Pearson Product-Moment Correlation Coefficient, Correlation And Dependence, Effect Size
19 Feb 2014
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What are correlations: scatterplots, correlations and causality. What are regressions? y = mx + b: multiple regressions. Examples: siddiqui, west, and stanovich (1998) The pearson correlation (r) coefficient is the statistic that indicates the degree to which two variables are related to one another in a linear fashion. Range r is between 1. 00 and + 1. 00. The probability is calculated using the student"s t statistic. Minimum r that is significant (for a p value of . 05) When multiple correlations are used, the results are typically shown in a correlation matrix. Three criteria must be satisfied to conclude that one variable causes another: covariation. There is a correlation between variables x and y: directionality. Variable x (the cause) precedes variable y (the effect): elimination of extraneous variables. No other variable may be responsible for the relationship between x and y. Correlational studies do not allow us to determine which variable is the cause and which variable is the effect.
