Descriptive, Correlational, and Inferential Statistics
Correlational statistics, which are described separately in Part C of this book, are a special subgroup of descriptive statistics. The purpose of correlational statistics is to describe the relationship between two or more variables for one group of participants. For instance, suppose a researcher is interested in the predictive validity of a college admissions test. The researcher could collect the admissions scores and the freshman GPAs for a group of college students. To determine the validity of the test for predicting GPAs, a statistic known as a correlation coefficient could be computed. Correlation coefficients range in value from 0.00 (no correlation between variables) to 1.00 (a perfect correlation).1 The meanings of these values are described in detail in Part C.