option linesize=72 nodate nonumber;
data bus;
input id  n  x  y;
if (id = 29 or id =2 or id=23) then T=1; else T=0;
datalines;
   1   1  26  35.0
   2   1  40  57.0
   3   7  32  34.3
   4   3  36  38.3
   5   2  27  37.5
   6   4  39  36.3
   7   4  29  31.3
   8   3  22  35.0
   9   1  34  30.0
   10  1  25  30.0
   11 10  37  40.5
   12  2  36  47.5
   13  1  20  30.0
   14  2  26  40.0
   15  2  31  30.0
   16  3  22  26.7
   17  5  25  34.0
   18  4  29  32.5
   19  3  24  28.3
   20  6  34  40.8
   21  7  28  29.3
   22  5  21  26.0
   23  4  40  47.0
   24  2  35  40.0
   25  3  24  30.0
   26  2  35  45.0
   27  2  31  37.5
   28  9  21  25.0
   29 17  36  51.1
   30  2  36  42.5
   31  1  35  45.0
   32  3  24  25.0
   ;
   proc reg;
   model y= x / influence;
   WEIGHT n;
   output r=R1 p=yhat;
   run;
   proc plot; plot R1*x;
   proc reg;
   model y= x T/ influence;
   output r=R2; 
   weight n;
   run;
   proc plot; plot R2*x;
   data bus1; set bus;
   if (id=29) then delete;
   run;
   proc reg;
   model y= x /influence;
   weight n;
   run;