help nptrend dialog: nptrend
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Title
[R] nptrend -- Test for trend across ordered groups
Syntax
nptrend varname [if] [in] , by(groupvar) [nodetail score(scorevar)]
Menu
Statistics > Nonparametric analysis > Tests of hypotheses > Trend test
across ordered groups
Description
nptrend performs the nonparametric test for trend across ordered groups
developed by Cuzick, which is an extension of the Wilcoxon rank-sum test
(see [R] rankum). A correction for ties is incorporated into the test.
nptrend is a useful adjunct to the Kruskal-Wallis test; see [R] kwallis.
Options
+------+
----+ Main +-------------------------------------------------------------
by(groupvar) is required; it specifies the group on which the data are to
be ordered.
nodetail suppresses the listing of group rank sums.
score(scorevar) defines scores for groups. When it is not specified, the
values of groupvar are used for the scores.
Example
. webuse sg
. nptrend exposure, by(group)
Saved results
nptrend saves the following in r():
Scalars
r(N) number of observations
r(p) two-sided p-value
r(z) z statistic
r(T) test statistic
Also see
Manual: [R] nptrend
Help: [ST] epitab, [R] kwallis, [R] signrank, [R] spearman, [R]
symmetry, [ST] strate
