Introduction

When research psychologists have collected a data set, they often organize the raw scores into what is called a distribution of scores by ranking all the scores from the lowest to the highest.

But if the data set is large, the researchers won't be able to make much sense of these raw scores.

So they reduce the information to a more manageable amount by calculating several numbers that can describe some important aspects of the distribution in a kind of "shorthand."

These special numbers are called descriptive statistics.