PSYC 2530 Chapter Notes - Chapter 5: Standard Deviation, Statistical Inference
19 Nov 2012
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Chapter 5: z-scores: location of scores and standardized distributions. A z-score establishes a relationship between the score, the mean, and the standard deviation. If every x value is transformed into a z-score, then the distribution of z-scores will have the following properties: same shape as the original distribution, (or m) = 0, (or s) = 1. The z-score distribution is called a standardized distribution: a standardized distribution is composed of scores that have been transformed to create predetermined values for and . standardized distributions are used to make dissimilar distributions comparable. In inferential statistics, z-scores provide an objective method for determining how well a specific score represents its population. A z-score near 0 indicates that the score is close to the population mean and, therefore, is representative. A z-score beyond +2. 00 (or -2. 00) indicates that the score is extreme and is noticeably different from the other scores in the distribution.
