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	Test dei Punteggi Normali di Van der Waerden	Test di Friedman
Campo	Statistica	Statistica
Famiglia	Hypothesis test	Hypothesis test
Anno di origine	1952	1937
Ideatore	Bartel Leendert van der Waerden	Milton Friedman
Tipo	Nonparametric k-sample comparison via normal scores	Nonparametric repeated-measures comparison (by ranks)
Fonte seminale	van der Waerden, B.L. (1952). Order Tests for the Two-Sample Problem and Their Power. Indagationes Mathematicae, 14, 453–458.	Friedman, M. (1937). The use of ranks to avoid the assumption of normality implicit in the analysis of variance. Journal of the American Statistical Association, 32(200), 675–701.
Alias	normal scores test, Van der Waerden k-sample test, Van der Waerden Testi — Normal Skor	Friedman two-way analysis of variance by ranks, Friedman rank test, Friedman Testi
Correlati	6	2
Sintesi	The Van der Waerden test is a nonparametric k-sample hypothesis test that converts observations into normal scores — the quantiles of a standard normal distribution — before comparing groups. Introduced by Bartel Leendert van der Waerden in 1952, it can achieve higher statistical power than the Kruskal-Wallis test when the underlying distributions are symmetric, making it a compelling bridge between rank-based and parametric methods.	The Friedman test is a nonparametric hypothesis test that compares three or more related conditions measured on the same blocks or subjects, serving as the rank-based alternative to repeated-measures ANOVA. It was introduced by Milton Friedman in 1937 and works on ordinal or continuous data without assuming normality.