The TEXT statement specifies text for the dialog box that appears on line 15 and begins in column 1. The RADIOBOX statement specifies that a radio box will appear in the dialog box. DEFAULT= specifies that the first radio button ( Greater Than or Equal To) will be selected by default. The RBUTTON statements specify the mutually exclusive choices for the radio buttons. SUBSTITUTE= gives the value that is substituted for the %3 in the preceding DIALOG statement if that radio button is selected. 
          text #15 @1 'Choose a comparison criterion:';
          radiobox default=1;
             rbutton #16 @5 'Greater Than or Equal To'
                             substitute='GE';
             rbutton #17 @5 'Less Than or Equal To'
                             substitute='LE';
             rbutton #18 @5 'Equal To' substitute='EQ';
quit;