Percentiles identify the percentage of scores that fall below a particular score. Correlational Statistics Correlational statistics assess the relationship between two or more sets of scores. A correlation may be positive or negative and vary from 0.00 to plus or minus 1.00. The existence of a correlation does not necessarily mean that one of the correlated variables causes changes in the other. Nor does the existence of a correlation preclude that possibility.
Correlations are commonly graphed on scatter plots.
Perhaps the most common correlational technique is the Pearson's product-moment correlation. You square the Pearson's product-moment correlation to get the coefficient of determination, which will indicate the amount of variance in one variable accounted for by another variable. Inferential Statistics Inferential statistics permit experimenters to determine whether their findings can be generalized from their samples to the populations they represent. Consider a simple experiment in which an experimental group that is exposed to a condition is compared to a control group that is not. The McGraw-Hill Companies.