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Hello everyone Just a small query about non parametric statistics..... It has been indicated to me that, when testing for differences between 2 groups, the Wilcoxon Signed Ranks Test and the Mann Whitney Test assume that the distribution of the two groups have the same shape. Even though these distributions do not have to be normal..do they have to have only 'one-peak'? Also, for the Mann Whitney test and Wilcoxon Signed Ranks Test it is stated in one text that the variables can be ordinal and in another text (when talking about the Mann Whitney test)it is also stated that the variable does not have to be on an interval scale; an ordinal scale is sufficient. However, I have been in conversation with various bods who say that a continuous scale is assumed. Can anyone shed some light? Many thanks, Kim.