options nodate nonumber ps=60 ls=72;
data;
infile "c:/documents and settings/jvevea/desktop/grades.txt";
input grades pared homework;

proc gplot;
   plot grades*pared;
   plot grades*homework;
proc glm;
   model grades = pared homework;
   output p=fit r=residual rstudent=extern;
proc gplot;
   plot residual*fit;
proc print;
run;