GMACRO
RE
Random 500 C1;
Normal 50 5.
Random 500 C2;
Normal 0 5.
Random 500 C3;
Normal 0 5.
Add C1 C2 C4.
Add C1 C3 C5.
Name C1 = 'true' C2 ='x error' C3 ='y error' C4 = 'pretest' C5 = 'posttest' 
random 500 C6;
normal 0 5.
let k1=min(C6)
let k2=median(C6)
let k3=max(C6)
code (k1:k2) 0 (k2:k3) 1 c6 c7
table c7
let C6=C7
erase C7
name C6='group'
Sign C6
Histogram 'Group'
let c7=c1 + c3 + (10*c6)
name c7='postgain'
Histogram 'pretest'.
Histogram 'postgain'.
Histogram 'pretest';
MidPoint;
Bar 'group'.
Histogram 'postgain';
MidPoint;
Bar 'group'.
Plot 'postgain'  * 'pretest';
Symbol 'group'.
Table 'Group';
Means 'pretest' 'postgain';
StDev 'pretest' 'postgain';
N 'pretest' 'postgain'.
TwoT 95.0 c7 c6;
alternative 0.
Regress 'postgain' 1 'Group'.
Regress 'postgain' 2 'pretest' 'Group'.
ENDMACRO