Example 18.3: Creating Notched Box-and-Whisker Plots

The BOXPLOT Procedure

Example 18.3: Creating Notched Box-and-Whisker Plots

The following statements use the flight delay data of Example 18.1 to illustrate how to create side-by-side box-and-whisker plots with notches:

   title 'Analysis of Airline Departure Delays';
   title2 'Using the NOTCHES Option';
   proc boxplot data=times;
      plot delay * day /
                   boxstyle = schematicid
                   cboxfill = ywh
                   nohlabel
                   notches
                   cboxes   = dagr
                   cframe   = vligb
                   idcolor  = salmon
                   vaxis    = axis1;
      id reason;
      label delay = 'Delay in Minutes';
   run;

The notches, requested with the NOTCHES option, measure the significance of the difference between two medians. The medians of two box plots are significantly different at approximately the 0.05 level if the corresponding notches do not overlap. For example, in Output 18.3.1, the median for December 20 is significantly different from the median for December 24.

Output 18.3.1: Notched Side-by-Side Box-and-Whisker Plots

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