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sum of squares

(symbol: SS) the number obtained by determining the deviation of each point in a data set from some value (such as a mean or predicted value), multiplying each deviation by itself, and adding the resulting products. Thus, for a set of variables xi,
Σ(xi – x̄)2,
where x̄ is the mean value of xi. For example, if an analysis yields a mean score of 5 but a person’s actual score is 7, the squared deviation for that individual is (7 − 5)2 = 22 = 4: This would be added to the squared deviations of all other individuals in the sample. Various types of sums of squares are calculated in analysis of variance, regression analysis, and other statistical procedures. See error sum of squares.

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Psychology term of the day

November 22nd 2024

strategic family therapy

strategic family therapy

a group of approaches to family therapy in which the focus is on identifying and applying novel interventions to produce behavioral change rather than on helping the family gain insight into the sources of their problems. Also called strategic intervention therapy.