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Table: Report one-way Kruskal-Wallis...
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Performs a one-way Kruskal-Wallis analysis on the data in one column of a selected Table and reports the results in the info window. This test is sometimes refered to as a one-way analysis of variance for non-normally distributed data.
Settings
- Column with data
- the label of the column whose data will be analyzed.
- Factor
- the label of the column with the names of the levels.
Algorithm
The analysis is done on the ranked data and consists of the following steps:
- 1. Rank all the N data points together, i.e. rank the data from 1 to N.
- 2. The test statistic is:
| K = (12 / (N(N+1)) Σi=1g ni (meanRanki)2 - 3(N+1), |
- where g is the number of levels, ni the number of data in i-th level and meanRanki the average rank of the i-th level.
- 3. The p value is approximated by the χ2 (K, g - 1) distribution.
© djmw 20120617