A small community organization consists of 20 families, of which 4 have one child, 8 have two children, 5 have three children, 2 have four children, and 1 has five children.
(a) If one of these families is chosen at random, what is the probability it has i children, i = 1, 2, 3, 4, 5?
(b) If one of the children is randomly chosen, what is the probability that child comes from a family having i children, i = 1, 2, 3, 4, 5?