options nocenter nodate ls=78;

data a;
  input readlev tvtime grade;
  cards;
9.9 3.1 1
10.7 2.2 1
12.0 1.3 1
12.2 5.3 2
13.0 4.1 2
13.7 3.0 2
14.1 7.3 3
14.8 6.4 3
16.0 5.2 3
16.1 9.3 4
16.9 8.1 4
18.2 7.2 4
18.1 11.4 5
18.7 10.3 5
20.2 9.2 5
;

proc plot;
  plot readlev*tvtime;
run;

proc reg;
  model readlev=tvtime;
run;

proc plot;
  plot readlev*tvtime=grade;
run;

proc reg;
  model readlev=tvtime grade;
run;

proc corr;
  var readlev tvtime grade;
run;