options ls=80;

data junk1;
input x1 x2 y;
cards;
14 25 301
19 32 327
12 22 246
11 15 187
;
proc reg data=junk1;
 model y=x1 x2/r;

proc reg data=junk1;
 model y=x1 x2/influence;          

proc plot data=junk1;
plot x1*x2;


data junk2;
input x1 x2 y;
cards;
14 25 301 
19 32 400 
12 22 246
11 15 187
;
proc reg data=junk2;
 model y=x1 x2/ influence r;          

data junk3;
input x1 x2 y;
cards;
14 25 301
17 200 327
12 22 246
11 15 187
;
proc reg data=junk3;
 model y=x1 x2/ influence r;

proc plot data=junk3;
plot x1*x2;

run;