Assumptions for the Kruskal-Wallis test are that within each sample the observations are independent and identically distributed and the samples are independent of each other. To perform a Kruskal-Wallis test in SAS, the same code was used to produce the Wilcoxon Rank Sum test.
Still use mpg data, and say we wish to test whether there are highway mpg (hwy) among the cars with different number of cylinders (cyl).
proc npar1way data = mpg wilcoxon; class cyl; var hwy; run;
The results indicate that there is a statistically significant difference among the four types of cars (chi-square with three degrees of freedom = 34.0452148.7657, p = <.0001).