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Basic Analysis and Graphing - SAS

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Chapter 5 Performing Oneway <strong>Analysis</strong> 153<br />

Nonparametric<br />

Table 5.13 Descriptions of Nonparametric Tests (Continued)<br />

Nonparametric Multiple<br />

Comparisons<br />

Provides several options for performing nonparametric multiple<br />

comparisons. These tests are based on ranks, <strong>and</strong> control for the overall<br />

alpha level, except for the Wilcoxon Each Pair test. The following tests<br />

are available:<br />

Wilcoxon Each Pair performs the Wilcoxon test on each pair, <strong>and</strong><br />

does not control for the overall alpha level. This is the nonparametric<br />

version of the Each Pair, Student’s t option found on the Compare<br />

Means menu.<br />

Steel-Dwass All Pairs performs the Steel-Dwass test on each pair.<br />

This is the nonparametric version of the All Pairs, Tukey HSD<br />

option found on the Compare Means menu.<br />

Steel With Control compares each level to a control level. This is the<br />

nonparametric version of the With Control, Dunnett’s option found<br />

on the Compare Means menu.<br />

Dunn With Control for Joint Ranks compares each level to a control<br />

level, similar to the Steel With Control option. The Dunn method is<br />

different in that it computes ranks on all the data, not just the pair<br />

being compared.<br />

Dunn All Pairs for Joint Ranks performs a comparison of each pair,<br />

similar to the Steel-Dwass All Pairs option. The Dunn method is<br />

different in that it computes ranks on all the data, not just the pair<br />

being compared.<br />

See Dunn (1964) <strong>and</strong> Hsu (1996).<br />

a. For the Wilcoxon, Median, <strong>and</strong> Van der Waerden tests, if the X factor has more than two levels, a<br />

chi-square approximation to the one-way test is performed. If the X factor has two levels, a normal<br />

approximation to the two-sample test is performed, in addition to the chi-square approximation to the<br />

one-way test.<br />

Nonparametric Report Descriptions<br />

All nonparametric reports are described in the following tables:<br />

• Table 5.14 on page 153<br />

• Table 5.15 on page 154<br />

• Table 5.16 on page 155<br />

Table 5.14 Descriptions of the Wilcoxon, Median, <strong>and</strong> Van der Waerden Tests<br />

Level<br />

Lists the factor levels occurring in the data.

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