Shared Concepts and Topics

Continuous-by-class effects generate the same design columns as continuous-nesting-class effects. Table 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 7.

Table 8: Example of Continuous-by-Class Effects

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 continuous-by-class effects together with pure continuous effects to test for homogeneity of slopes.