In an increasingly data-driven world, it is more important than ever for students as well as professionals to better understand basic statistical concepts. 100 Questions (and Answers) About Statistics addresses the essential questions that students ask about statistics in a concise and accessible way. It is perfect for instructors, students, and practitioners as a supplement to more comprehensive materials, or as a desk reference with quick answers to the most frequently asked questions.

What Are Measures of Variability, and Why Are They Used?

What Are Measures of Variability, and Why Are They Used?

Measures of variability such as the range, standard deviation, and variance are the second type of descriptive statistic that one needs to fully describe the characteristics of a set of data. As you already know, measures of central tendency are the first type.

Measures of variability, also called spread or dispersion, reflect how different scores are from one another. More accurately stated, variability is the distance or the amount that any score in a set of scores differs from a particular score. That score, in almost all measures of variability, turns out to be the average score—in particular, the mean.

The three descriptive statistics that are used to measure variability in a set of scores are ...