40 Statistical interaction refers to which of the following?

a) Association exists between two vanables

b) The degree of association between two variables varies gicatly over the partial levels of a control vanable.

c) The partial association is the same at each level of the control variable, but it is different from the overall bivariate association. ignoring the control vanable.

d) For a collection of three variables, each pair of vanables is associated.

e) All of the above