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
