## Friedman Test

Friedman test is used to test the difference between treatments across multiple test subjects. Friedman Test is a non-parametric alternative to the parametric Two-Way ANOVA.

## Formula:

### $F_R =\dfrac{12}{nk(k+1)}\sum_{j=1}^k R_{\cdot j}^2-3n(k+1)$

where

• $k$ is the number of treatments
• $n$ is the number of blocks
• $R_{\cdot j}$ is the sum of the ranks for $j^{th}$ treatment

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