ABSTRACT
This chapter explores a range of Descriptive Statistics that Measure the degree of Dispersion or scatter around the three most commonly used Measures of Central Tendency: the Arithmetic Mean, Mode and Median; this led naturally to a consideration of how the data is scattered, or the Shape of the data set. It explores the concept of 'skewness' and 'peakiness'. The difference between the Maximum and the Minimum values expresses how widely scattered the values are within the data set in an absolute sense. The Average Absolute Deviation of a range of data is the average 'absolute' distance of each data point from the Arithmetic Mean of all the data points, ignoring the sign depicting whether each point is less than or greater than the Arithmetic Mean. The main problem with Variance and Standard Deviation as Measures of Dispersion is that of the scale and units of measurement used.
