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Measures of Dispersion

Measures of Dispersion

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.

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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

Measures of Dispersion

This powerpoint introduces and defines the terms range, deviation from the mean, mean absolute deviation, and variance. There are also examples on the same data set to illustrate these concepts.

Source: Greene

Calculating Variance

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

Source: YouTube

Mean Absolute Deviation

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

Source: YouTube