PSY 201 Chapter Notes - Chapter 4: Statistic, Standard Deviation, Statistical Parameter
30 Jul 2018
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Variability - provides a quantitative measure of the differences between scores in a distribution and describes the degree to which the scores are spread out or clustered together. The purpose for measuring variability is to obtain an objective measure of how the scores are spread out in a distribution. In general, a good measure of variability serves two purposes: Describes the distribution (tells whether the scores are clustered close together or spread out over a large distance). Variability measures how well an individual score (or group of scores) represents the entire distribution. In other words, it provides information about how much error to expect if you are using a sample to represent a population. Three measures of variability: range, standard deviation, and variance. Range - the distance covered by the scores in a distribution, from smallest to largest score. For continuous variables, range = url for xmax - lrl for xmin.
