A variable such as z, whose value is z = x1x2 is added to a general linear model in order to account for potential effects of two variables x1 and x2 acting together. This type of effect is _____.
a. impossible to occur
b. called interaction
c. called multicollinearity effect
d. called transformation effect
Question 2
When a waiting system is in steady-state operation, the number of units in the system is not changing.
Indicate whether the statement is true or false