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 Is the Normal or Bell-Shaped Curve?

### What Is the Normal or Bell-Shaped Curve?

The normal or bell-shaped curve, as you see in Figure 67.1, is a visual representation of a distribution of data that has three very special characteristics. Most important, because of these characteristics, the normal curve becomes the basis for much of how inferential statistics operates.

In this example, the x-axis represents values (such as how smart people are), and the y-axis represents the frequency or probability of those values (lots of people or very few people and everything in between).

### Figure 67.1 The normal curve

The first key characteristic is that the mean, median, and mode are all equal to one another. The central-most point in the distribution of scores represents the mean, the median, and the mode.

Second, the ...