The Friedman test, also sometimes referred to as Friedman’s two-way analysis of variance by ranks, is a non-parametric statistical test used to investigate whether groups of three or more repeated ...

Journal of the Royal Statistical Society. Series C (Applied Statistics), Vol. 55, No. 4 (2006), pp. 507-524 (18 pages) Generalized estimating equations for correlated repeated ordinal score data are ...