Kruskal-Wallis test performing

With the one-way ANOVA, most statistical packages implement a series of followup tests to determine exactly where any differences lie. Similar procedures exist to allow follow-up after a significant Kruskal-Wallis test, but unfortunately they are not widely implemented in statistical packages. There would be no point in doing so in the present case, but if another data set proves significant and you want to perform follow-up tests, you will either have to resort to a very powerful (and probably not very friendly) statistical package, or do the calculation manually. The latter is tedious, but recipes are available. (A clear account is available in Zar J.H., 1999, Biostatistical Analysis, Prentice Hall, NJ pp. 223-226.)... 

Parametric data were presented as mean SD. To determine differences in glutamate concentrations, a repeated-measures analysis of variance was performed. The cutaneous sensation, hind-limb motor function, and morphological changes of the spinal cord were analyzed with a non-parametric method (Kruskal-Wallis test) followed by the Mann-Whitney U-test. 

The grading of reflection reports from the three student populations is analyzed and correlated with a number of other statistics and performance indicators. All data were collected in Microsoft Excel and unported into Statgraphics Centurion XV for further analysis [7], We performed ANOVA tests, multiple range test or Kruskal-Wallis tests, and f-tests on the gathered information. 

To further identify which group is different, a Dunn s post-test is performed. This test compares the difference in the median for each group pair. If the statistic of the pair is greater than the critical value, then the null hypothesis that there is no significant difference between the medians of the pair is rejected. With smaller sample sizes the power of the Kruskal-Wallis test decreases, so these results need to be analyzed carefully. 

The tests performed were the same used for the analysis of individual motivational values. The Kruskal-Wallis test and the Dunn s post-test are used for the first comparison, and the Wilcoxon signed-ranked test is used for the second comparison. 

Statistical Analysis. T-tests, Kruskall-Wallis and analyses of variances were performed using SAS, a statistical computer software program developed by Statistical Analysis Systems, Inc. 

All data are presented as means S.E. A statistical analysis was performed using the Kruskal-Wallis and Steel test. A probability value of less than 0.05 was considered significant. 

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