3.16 The hierarchical structure model for joint attribute distribution

A hierarchical model assumes that attributes are structured. A hierarchical model simply rules out some latent classes such that the mass function of an impermissible latent class is fixed at 0. Some examples are given below:

What is the number of parameters under each of structure above?

An example

What are the joint probabilities of two attributes in the following table under a linear structure where A1 is a prerequisite for A2?