This example uses the SAS data set React
created in Example 83.3. The data set contains the variable Stim
, which represents Stimulant 1 or 2, and the variable Time
, which contains the reaction times observed for subjects under the stimulant.
The following statements request Hodges-Lehmann estimation of the location shift between the two groups. Stim
is the CLASS variable, and Time
is the analysis variable. The HL option requests Hodges-Lehmann estimation. The ALPHA= option sets the confidence level for
the Hodges-Lehmann confidence limits. The HL option in the EXACT statement requests exact confidence limits for the estimate
of location shift. The ODS SELECT statement selects which tables to display. Output 83.4.1 shows the Hodges-Lehmann results.
proc npar1way hl alpha=.02 data=React; class Stim; var Time; exact hl; ods select WilcoxonScores HodgesLehmann; run;
The HL option invokes the WILCOXON option, which produces a table of Wilcoxon scores (Output 83.4.1). The Hodges-Lehmann estimate of location shift is 0.35, and the asymptotic confidence limits are 0.00 and 0.82. The confidence interval midpoint equals 0.41, which can also be used as an estimate of the location shift. The ASE estimate of 0.1762 is based on the length of the confidence interval. The exact confidence limits are 0.00 and 1.33.
Output 83.4.1: Hodges-Lehmann Estimate of Location Shift