| dispersion | spread of the scores around the mean
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| range | difference between the highest and lowest scores in a distribution
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| average deviation | average amount that each score in a distribution deviates from the distribution's mean
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| absolute value of a score | value of the score without regard to its sign
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| variance | average of the squared deviations of scores from the mean
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| standard deviation | square root of the variance
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| sum of squares | sum of the squared deviation of the scores from the mean
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| standard score | deviation of a raw score from the mean in standard deviation units; also known as a z score
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| z score | deviation of a raw score from the mean in standard deviation units; also known as a standard score
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2003 McGraw-Hill Higher Education