Free Professional Development

Or

Author:
Nate Muckley

Learn about frequency distributions, their various aspects, and how to create them.

Frequency distributions are very useful, in and out of the statistics classroom. Learn about them, and their creation!

There's also a picture of a cat.

Tutorial

**UNGROUPED** data is the raw data, the numbers

**GROUPED** data is organized into a frequency distribution with ranges instead of individual numbers. Makes a large amout of data much more manageable.

A **FREQUENCY DISTRIBUTION** is a table of the results of a sample; how often results occur.

In the frequency distribution table, there are two categories, the **CLASSES**, or ranges of data, and the **FREQUENCY**, or the number of sample data in each class.

The classes have **UPPER **and **LOWER CLASS LIMITS**, which are the highest and lowest numbers of the class, respectively.

A **CLASS WIDTH** is the size of the class, or the Upper limit minus the Lower limit.

The **CLASS MARK** (or **MIDPOINT**) is the point in the middle of a particular class. It is found by taking the average of the class limits.

The **CLASS BOUNDARIES** are the numbers that separate the classes. They are found by taking the average of the limits between two classes.

* for clarification, the class mark is the middle OF A CLASS, and the class boundaries are the middle BETWEEN CLASSES.

A **HISTOGRAM** is a bar graph of the data in the frequency distribution.

*for more information on Histograms, click **HERE**** **to check out my packet on them.

*See the pictures below to observe these definitions.*

Source: flickr.com