The EXACT statement requests exact tests and confidence limits for selected statistics. The statisticoptions identify which statistics to compute, and the computationoptions specify options for computing exact statistics. For more information, see the section Exact Tests.
Note: PROC NPAR1WAY computes exact tests by using fast and efficient algorithms that are superior to direct enumeration. Exact tests are appropriate when a data set is small, sparse, skewed, or heavily tied. For some large problems, computation of exact tests might require a large amount of time and memory. Consider using asymptotic tests for such problems. Alternatively, when asymptotic methods might not be sufficient for such large problems, consider using Monte Carlo estimation of exact pvalues. You can request Monte Carlo estimation by specifying the MC computationoption in the EXACT statement. For more information, see the section Computational Resources.
The statisticoptions specify which exact tests to compute. Table 71.3 lists the available statisticoptions and the exact statistics that are computed. Descriptions of the statisticoptions follow Table 71.3 in alphabetical order.
Exact pvalues are available for all nonparametric tests of location and scale differences that are produced by PROC NPAR1WAY. These include tests based on the following scores: Wilcoxon, median, Van der Waerden (normal), Savage, SiegelTukey, AnsariBradley, Klotz, Mood, and Conover. Additionally, exact pvalues are available for tests that use the raw input data as scores. The procedure computes exact pvalues when the data are classified into two levels (twosample tests) and when the data are classified into more than two levels (multisample tests). Twosample tests are based on simple linear rank statistics. Multisample tests are based on oneway ANOVA statistics.
Exact pvalues are also available for the twosample KolmogorovSmirnov test. Exact confidence limits are available for the HodgesLehmann estimate of location shift.
If you list no statisticoptions in the EXACT statement, PROC NPAR1WAY computes all available exact pvalues for those tests that you request in the PROC NPAR1WAY statement.
Table 71.3: EXACT Statement Statistic Options
Statistic Option 
Exact Test 

AnsariBradley test 

Conover test 

HodgesLehmann confidence limits 

Klotz test 

Twosample KolmogorovSmirnov test 

Median test 

Mood test 

Savage test 

Test with input data as scores 

SiegelTukey test 

Van der Waerden (normal scores) test 

Wilcoxon test for twosample data or 

KruskalWallis test for multisample data 
You can specify the following statisticoptions in the EXACT statement.