T Test Correlation Point Biserial Model. A point biserial correlation is just a Pearsons r computed on a pair of variables where one is continuous and the other is dichotomized. It is divded into independent measures and repeated measures.
Point Biserial Correlation Example from www.slideshare.net
The technical term for the correlation used in exam item analysis is a point-biserial. In a point-biserial correlation test scores on a continuous scale are compared to a single item that has only two possible values. Point biserial model having 03 effect size 005 alpha and 095 power.
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Correlation needs two variables where one observation in X variable is paired with one in Y variable. You can check for this assumption by plotting your continuous variable in each of your two groups and visually identifying if the spread of the data is similar. The range of a point biserial correlation in from -1 to 1. Poin t Biserial Correlation Tests procedure window by expanding Correlation then Correlation then clicking on Test Inequality and then clicking on Point Biserial Correlation Tests.
