OPTIONS LS=75;

DATA cig;
   INPUT  tar     nic      wt       co;
   CARDS;
    14.1    0.86    0.9853    13.6
    16.0    1.06    1.0938    16.6
    29.8    2.03    1.1650    23.5
     8.0    0.67    0.9280    10.2
     4.1    0.40    0.9462     5.4
    15.0    1.04    0.8885    15.0
     8.8    0.76    1.0267     9.0
    12.4    0.95    0.9225    12.3
    16.6    1.12    0.9372    16.3
    14.9    1.02    0.8858    15.4
    13.7    1.01    0.9643    13.0
    15.1    0.90    0.9316    14.4
     7.8    0.57    0.9705    10.0
    11.4    0.78    1.1240    10.2
     9.0    0.74    0.8517     9.5
     1.0    0.13    0.7851     1.5
    17.0    1.26    0.9186    18.5
    12.8    1.08    1.0395    12.6
    15.8    0.96    0.9573    17.5
     4.5    0.42    0.9106     4.9
    14.5    1.01    1.0070    15.9
     7.3    0.61    0.9806     8.5
     8.6    0.69    0.9693    10.6
    15.2    1.02    0.9496    13.9
    12.0    0.82    1.1184    14.9
    10       .        .       .
  ;
RUN;

PROC CORR;
   VAR co;
   WITH tar nic wt;
RUN;

PROC GPLOT;  
   PLOT co*tar;  
   PLOT co*nic;  
   PLOT co*wt;  
   SYMBOL1 V=DOT I=R C=R;
run;

PROC G3D;
   SCATTER tar*nic=co;
QUIT;

PROC REG SIMPLE;
   MODEL co=nic wt tar/SS1 SS2; 
   *nic_wt: TEST nic=0, wt=0;
   MODEL co=tar/SS1 SS2; 
   PLOT co*tar;  /* scatterplot with goodies */  
   PLOT r.*nqq.; /* normal plot */
RUN;