options linesize =72 nodate nonumber;
data traffic;
input density speed;
datalines;
  20.4  38.8
  27.4  31.5
 106.2  10.6
  80.4  16.1
 141.3   7.7
 130.9   8.3
 121.7   8.5
 106.5  11.1
 130.5   8.6
 101.1  11.1
 123.9   9.8
 144.2   7.8
  29.5  31.8
  30.8  31.6
  26.5  34.0
  35.7  28.9
  30.0  28.8
 106.2  10.5
  97.0  12.3
  90.1  13.2
 106.7  11.4
  99.3  11.2
 107.2  10.3
 109.1  11.4
 ;
 data; set traffic;
 rootspeed = sqrt(speed);
 squared = density*density;
 logspeed = log(speed);
 run;
 proc reg;
 model speed = density squared;
 output residual = R predicted = speedhat;
 run;
 proc plot;
 plot R*speedhat;
 run;
 proc reg;
 model rootspeed = density squared;
 output residual = Z predicted = squaredhat;
 run;
 proc plot;
 plot Z*squaredhat;
 run;
 proc reg;
 model logspeed = density squared;
 output residual = Z1 predicted = logspeedhat;
 run;
 proc plot;
 plot Z1*logspeedhat;
 run;