Kruskal-Wallis Rank Sum Test

The Kruskal-Wallis rank test is a nonparametric alternative to a one-way analysis of variance. The null hypothesis is that the true location parameter for y is the same in each of the groups. The alternative hypothesis is that it is different in at least one of the groups. Unlike one-way ANOVA, this test does not require normality.

To perform a Kruskal-Wallis rank sum test

Choose Statistics __image\ebd_ebd32.gif Compare Samples __image\ebd_ebd33.gif k Samples __image\ebd_ebd34.gif Kruskal-Wallis rank sum. The dialog shown below appears.

__image\kruskwal.gif

The Kruksal-Wallis rank test has the following options:

Data

Data Set

Select a data set from the dropdown list or type the name of a data set. You can also type into the Data Set edit field any expression that evaluates to a data set.

Variable

Select the columns of the data set to include in the analysis. To include all columns, select ALL. Making no selection has the same effect since ALL is the default value.

Grouping Variable

Specify a grouping variable to use when resampling observations.

Results

Save As

Enter the name for the object in which to save the results of the analysis.

Print Results

Select this to print out the results of the analysis in the designated output window.

Related S-PLUS language functions

kruskal.test, menuKruskal