Continuousbyclass effects generate the same design columns as continuousnestingclass effects. Table 19.8 shows the construction of the X*A effect. The two columns for this effect are the same as the columns for the X(A) effect in Table 19.7.
Data 
I 
X 
A 
X*A 


X 
A 

X 
A1 
A2 
X*A1 
X*A2 

21 
1 
1 
21 
1 
0 
21 
0 

24 
1 
1 
24 
1 
0 
24 
0 

22 
1 
1 
22 
1 
0 
22 
0 

28 
2 
1 
28 
0 
1 
0 
28 

19 
2 
1 
19 
0 
1 
0 
19 

23 
2 
1 
23 
0 
1 
0 
23 
You can use continuousbyclass effects together with pure continuous effects to test for homogeneity of slopes.