Shared Statistical Concepts

Continuous-Nesting-Class Effects

When a continuous variable nests or crosses with a classification variable, the design columns are constructed by multiplying the continuous values into the design columns for the classification effect (Table 4.12).

Table 4.12: Example of Continuous-Nesting-Class Effects

Data

 

I

 

A

 

X(A)

X

A

 

$\beta _0$

 

A1

A2

 

X(A1)

X(A2)

21

1

 

1

 

1

0

 

21

0

24

1

 

1

 

1

0

 

24

0

22

1

 

1

 

1

0

 

22

0

28

2

 

1

 

0

1

 

0

28

19

2

 

1

 

0

1

 

0

19

23

2

 

1

 

0

1

 

0

23


This model estimates a separate intercept and a separate slope for X within each level of A.