Author:
Al Greene

To introduce new terms and definitions pertaining to measures of dispersion, and give examples of each.

This packet has a slideshow that defines all of the measures of dispersion and gives examples of each. There is also a video that gives a good example of how measures of dispersion are used and interpreted.

Tutorial

To begin this packet, you should be familiar with a few new terms:

Range - The difference between the largest and smallest observations in a data set.

Deviation from the mean - The difference between each data point and the mean.

Mean absolute deviation - The mean of all the positive distances of each point from the mean.

Variance - The mean of the squared deviations of each point from the mean.

All of these definitions will be discussed further in depth, with examples, below.

Source: Greene

This video shows the formula for calculating sample variance, and gives a detailed, step by step example on a small data set.

Source: YouTube

This video gives a straightforward example on calculating mean absolute deviation of a data set.

Source: YouTube