How many parameters are needed to describe this distribution?
Consider a distribution consisting of three binary variables which admit the factorisation:
How many parameters are needed to specify distributions of this form?
Note that this is different to the general case where all variables might be dependent:
In the case where we have no information about the variable dependency, we need to specify 8-1=7 parameters to define
the distribution. There are
In the given case, b's value is sufficient to know the distribution of a. So some simplification is possible. A way to
think about the situation is to consider 5 coins:
Drawing a graph is another way to model this problem.