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.
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.