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Fisher least significant difference test

a statistical procedure to compare pairs of means, conducted after an F test has revealed that at least one pair of means is significantly different. The test calculates the smallest value that would be significantly different from chance when subtracting one mean from another mean. If the absolute value of the actual difference between a pair of means is larger than this least significant difference (LSD), a researcher can reject a null hypothesis that the means are equal and conclude that they are significantly different. Also called protected t test. [Ronald Aylmer Fisher]

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Psychology term of the day

May 9th 2024

hierarchically nested design

hierarchically nested design

any research design that involves several levels of sampling, such that the entities on the lower levels of the design are nested or subsumed within higher order groups. For example, a hierarchically nested design for an educational study might involve students (A), who are nested within classrooms (B), which are nested within schools (C), which are further nested within school districts (D). Several statistical procedures (e.g., analysis of variance, regression analysis, hierarchical linear models) also incorporate a hierarchical aspect. Also called hierarchical design; nested design.