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I have a repeated measurement of n=452 participants. The Friedman test of SPSS gives df=2, chi-square 36.970 whereas below is the output of R and python. I cannot explain this difference for chi-square value (30 from R and python vs 36 from SPSS) although it is not too much. Can anyone help me understand this?

#Friedman rank sum test in R        
friedman.test(data.matrix(x))
data:  data.matrix(x)
Friedman chi-squared = 30.389, df = 2, p-value = 2.518e-07

#----------------------------------------------

#Friedman Test in python
friedmanchisquare(x1, x2, x3)

FriedmanchisquareResult(statistic=30.38907395069963, pvalue=2.5182360483490374e-07)

SPSS output enter image description here

Artemis-a
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1 Answers1

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This was posted also in Cross Validated here. The issue was "fuzz" in the input data that was treated differently by the packages.

David Nichols
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