In CBC Counts Analysis the report shows the chi-square values of the interaction effects. For main effects it is no problem to calculate the chi-square value with pearson's formula. But I have no idea how to calculate the value for the interaction effects.
Imagine the following example: I have two attributes with three levels each. That means, I have (3-1)*(3-1) = 4 degrees of freedom and 9 count values of two-way-occurances (combination of level_1 of attribute_1 with level_1 of attribute_2, ..., level_3 of attribute_1 with level_3 of attribute_2).
I do not know what to do with these 9 two-way-occurances to get the right chi-square value provided by the sawtooth software.
Can you help me, please?