
Chapter 18
786
18.6 FRIEDMAN TEST
Friedman test
13
is the non-parametric alternative to randomized block design. Developed by
M.Friedman in 1937, the Friedman test is used when assumptions of ANOVA are not met or
when researchers have ranked data.
14
In fact, the Friedman test is very useful when data are
ranked within each block. The Friedman test is based on the following assumptions:
1. The blocks are independent.
2. There is no interaction between blocks and treatments.
3. Observations within each block can be ranked.
The null and alternative hypotheses in the Friedman test can be set as
H
0
: The distribution of k
treatment populations are identical. ...