An inflammatory disease is a fatal genetic disease occurring mainly in children, belonging to a particular sly community. Suppose that we limit ourselves to families which have (a) exactly three...

An inflammatory disease is a fatal genetic disease occurring mainly in children,

belonging to a particular sly community. Suppose that we limit ourselves to families

which have (a) exactly three children, and (b) which have both parents carrying the

inflammatory disease. For such parents, the probability that a child will get the disease

is 1/4. Assume each child is independent of one another. Let X be the random variable

representing the number of children that will have the disease. Which distribution does

X follow? What will be the pdf of X? Find E(X) and V(X).