The NPAR1WAY Procedure

requests an analysis of Ansari-Bradley scores. See the section Ansari-Bradley Scores for more information. The ADJUST option subtracts class medians from the input observations before performing the analysis.

adjusts for location differences among classes before performing tests for scale differences. The ADJUST option applies to the following analyses: Ansari-Bradley (AB), Klotz (KLOTZ), Mood (MOOD), and Siegel-Tukey (ST). If you specify the ADJUST option, PROC NPAR1WAY subtracts the corresponding class median from each observation before scoring the data and performing the scale tests that you request.

You can also request adjustment for an individual scale test by specifying ADJUST in parentheses after the scale test option; for example, you can specify ST(ADJUST) to adjust by class medians before performing the Siegel-Tukey test.

specifies the level of the confidence limits for location shift, which you request with the HL option. The value of must be between 0 and 1, and the default is 0.05. A confidence level of produces % confidence limits. The default of ALPHA=0.05 produces 95% confidence limits for the Hodges-Lehmann estimate.

requests a standard analysis of variance on the raw data.

requests an analysis of Conover scores. See the section Conover Scores for more information.

suppresses the continuity correction for the Wilcoxon two-sample test and the Siegel-Tukey two-sample test. See the section Continuity Correction for more information.

requests the one-sided Kolmogorov-Smirnov and statistics and their asymptotic p-values, in addition to the two-sided D statistic produced by the EDF option for two-sample data. The D option invokes the EDF option. The statistics D+ and D– are provided by default if you request exact Kolmogorov-Smirnov statistics with the KS option in the EXACT statement for two-sample data. See the section Tests Based on the Empirical Distribution Function for details about Kolmogorov-Smirnov statistics.

names the SAS data set to be analyzed by PROC NPAR1WAY. If you omit the DATA= option, the procedure uses the most recently created SAS data set.

requests the Dwass, Steel, Critchlow-Fligner multiple comparison procedure, which is based on pairwise two-sample rankings. This procedure is available for multisample data, where the number of CLASS variable levels is greater than 2. See the section Multiple Comparisons Based on Pairwise Rankings for more information.

requests statistics based on the empirical distribution function. These include the Kolmogorov-Smirnov and Cramér–von Mises tests and, if there are only two classification levels, the Kuiper test. See the section Tests Based on the Empirical Distribution Function for more information.

The EDF option produces the Kolmogorov-Smirnov D statistic for two-sample data. You can request the one-sided D+ and D– statistics for two-sample data with the D option.

requests the Fligner-Policello test for two-sample data. See the section Fligner-Policello Test for more information.

The REFCLASS= option specifies which of the two CLASS variable levels (samples) to use as the reference class X for the difference between class placement sums, . REFCLASS=1 refers to the first class that is listed in the “Fligner-Policello Placements” table, and REFCLASS=2 refers to the second class listed. The table displays class levels in the order in which they appear in the input data set. REFCLASS=class-value identifies the reference class by the formatted value of the CLASS variable. By default, the reference class is the second class listed in the “Fligner-Policello Placements” table (REFCLASS=2).

requests Hodges-Lehmann estimation of the location shift for two-sample data. The HL option provides asymptotic confidence limits for the location shift. These are sometimes known as Moses confidence limits. See the section Hodges-Lehmann Estimation of Location Shift for details. You can specify the level of the confidence limits by using the ALPHA= option. The default of ALPHA=0.5 produces 95% confidence limits for the location shift.

The REFCLASS= option specifies which of the two CLASS variable levels (samples) to use as the reference class X for the location shift, Y – X. REFCLASS=1 refers to the first class that is listed in the “Wilcoxon Scores” table, and REFCLASS=2 refers to the second class listed. The table displays class levels in the order in which they appear in the input data set. REFCLASS=class-value identifies the reference class by the formatted value of the CLASS variable.

By default, PROC NPAR1WAY uses the larger of the two classes as the reference class X to compute the Hodges-Lehmann location shift, Y – X. If both class have the same number of observations, PROC NPAR1WAY uses the class that appears second in the input data set as the reference class.

requests an analysis of Klotz scores. See the section Klotz Scores for more information. The ADJUST option subtracts class medians from the input observations before performing the analysis.

requests an analysis of median scores. When there are two classification levels, this option produces the two-sample median test. When there are more than two samples, this option produces the multisample median test, which is also known as the Brown-Mood test. See the section Median Scores for more information.

treats missing values of the CLASS variable as a valid class level.

requests an analysis of Mood scores. See the section Mood Scores for more information. The ADJUST option subtracts class medians from the input observations before performing the analysis.

suppresses the display of all output. You can use the NOPRINT option when you only want to create an output data set. Note that this option temporarily disables the Output Delivery System (ODS). For more information, see Chapter 20: Using the Output Delivery System.

controls the plots that are produced through ODS Graphics. Plot-requests specify the plots to produce, and plot-options control the appearance and content of the plots. You can specify plot-options in parentheses after a plot-request. A global-plot-option applies to all plots for which it is available, unless it is altered by a specific plot-option. You can specify global-plot-options in parentheses after the PLOTS option.

When you specify only one plot-request, you can omit the parentheses around the request. For example:

plots=all
plots=wilcoxonboxplot
plots=(wilcoxonboxplot edfplot)
plots(only)=(medianplot normalboxplot)

ODS Graphics must be enabled before plots can be requested. For example:

ods graphics on;
proc npar1way plots=wilcoxonboxplot;
   variable response;
   class treatment;
run;
ods graphics off;

For more information about enabling and disabling ODS Graphics, see the section Enabling and Disabling ODS Graphics in Chapter 21: Statistical Graphics Using ODS.

If ODS Graphics is enabled but you do not specify the PLOTS= option, PROC NPAR1WAY produces all plots that are associated with the analyses that you request. If you request a plot with the PLOTS= option but do not request the corresponding analysis, PROC NPAR1WAY automatically invokes that analysis. For example, if you specify PLOTS=CONOVERBOXPLOT but do not also specify the CONOVER option in the PROC NPAR1WAY statement, PROC NPAR1WAY produces the Conover scores analysis in addition to the box plot.

You can suppress default plots and request specific plots by using the PLOTS(ONLY)= option; PLOTS(ONLY)=(plot-requests) produces only the plots that are specified as plot-requests. You can suppress all plots with the PLOTS=NONE option. The PLOTS= option has no effect when you specify the NOPRINT option.

PROC NPAR1WAY provides box plots of scored data, median plots, and empirical distribution plots. See Figure 65.7, Output 65.1.2, Output 65.1.4, and Output 65.2.2 for examples of plots that PROC NPAR1WAY produces. For general information about ODS Graphics, see Chapter 21: Statistical Graphics Using ODS.

Global Plot Options

A Global-plot-option applies to all plots for which the option is available unless it is altered by a specific plot-option. You can specify the following global-plot-options in parentheses after the PLOTS option. You cannot specify both STATS and NOSTATS as global-plot-options in the same statement.

Plot Requests

The following plot-requests are available with the PLOTS= option.

Plot Options

The following plot-options are available for any plot-request. You cannot specify both STATS and NOSTATS as plot-options for the same plot. If you specify NOSTATS as a global-plot-option, specifying STATS as an individual plot-option overrides the global-plot-option for the individual plot and displays statistics in the plot.

requests an analysis of Savage scores. See the section Savage Scores for more information.

requests an analysis that uses input data as scores. This option gives you the flexibility to construct any scores for your data with the DATA step and then analyze these scores with PROC NPAR1WAY. See the section Scores for Linear Rank and One-Way ANOVA Tests for more information.

To produce the two-sample permutation test that is known as Pitman’s test, provide raw (unscored) data in the input data set and specify the SCORES=DATA option in the EXACT statement. See the section Exact Tests for more information.

requests an analysis of Siegel-Tukey scores. See the section Siegel-Tukey Scores for more information. The ADJUST option subtracts class medians from the input observations before performing the analysis.

requests an analysis of Van der Waerden (normal) scores. See the section Van der Waerden (Normal) Scores for more information.

requests an analysis of Wilcoxon scores. When there are two classification levels (samples), this option produces the Wilcoxon rank-sum test. For any number of classification levels, this option produces the Kruskal-Wallis test. See the section Wilcoxon Scores for more information.