d.f.


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d.f.

Abbreviation for degrees of freedom , under degree.
Farlex Partner Medical Dictionary © Farlex 2012

degrees of freedom

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d.f.

In defining the properties of a statistical sample, the number of independent observations in a quantity. For example, if a sample contains a total of 10 children who are being classified by hair color (brown, black, or blond) and it is known that four of the children have blond hair, then there are two degrees of freedom. If, at the beginning of the investigation, the hair color of all the subjects is unknown, there are three degrees of freedom.
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
Abundance, species richness and diversity (H[prime]) of 1992 pitfall samples did not respond significantly to burning frequency (GLM t = 0.47, 1 d.f., P = 0.72; GLM t = 0.45, 1 d.f., P = 0.73; GLM t = 0.10, 1 d.f., P = 0.94) or burning in 1992 (GLM t = 0.04, 1 d.f., P = 0.97; GLM t = 0.33, 1 d.f., P = 0.80; GLM t = 0.22, 1 d.f., P = 0.86).
Abundance, species richness [ILLUSTRATION FOR FIGURE 2A, B OMITTED] and diversity (H[prime]) of 1994 light trap samples did not respond significantly to time of sampling, burning frequency (GLM t = 1.46, 8 d.f., P = 0.38; GLM t = 1.62, 8 d.f., P = 0.35; GLM t = 1.84, 8 d.f., P = 0.32) or burning in 1994 (GLM t = 1.48, 8 d.f., P = 0.18; GLM t = 1.64, 8 d.f., P = 0.14; GLM t = 1.49, 8 d.f., P = 0.17).
The number of Lepidoptera counted in visual transects in 1994 declined significantly with burning in 1994 (GLM t = 2.77, 8 d.f., P [less than] 0.05) and declined nonsignificantly with burning frequency [ILLUSTRATION FOR FIGURE 3 OMITTED].