Cochran's Q Test - Description

Description

Cochran's Q test is

H0: The treatments are equally effective.
Ha: There is a difference in effectiveness among treatments.

The Cochran's Q test statistic is

T = k\left(k-1\right)\frac{\sum\limits_{j=1}^k \left(X_{\bullet j} - \frac{N}{k}\right)^2}{\sum\limits_{i=1}^b X_{i\bullet}\left(k-X_{i\bullet}\right)}

where

k is the number of treatments
X• j is the column total for the jth treatment
b is the number of blocks
Xi • is the row total for the ith block
N is the grand total

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