Answer Happy

38. An experiment consists of recording the sex composition, in order of their births, of a four-child family in which the children were born at different times. Assuming that a boy is equally likely as a girl to be born into a family, what is the probability that a four-child family chosen at random will have the following? (a) Three girls and a boy in the family. a (b) A youngest child in the family who is a boy. (C) An oldest child and a youngest child in the family who are both boys.