The Smith family was one of the first to come to the U.S. They had 6 children. Assuming that the probability of a child being a girl is 0.5, find the probability that the Smith family had: at least 2 girls? at most 5 girls?
At least 2 girls =(6 nCr 2+6 nCr 3+6 nCr 4+6 nCr 5+6 nCr 6) = 57 / 2^6 =57 / 64
At most 5 girls =(6 nCr 5+6 nCr 4+6 nCr 3+6 nCr 2+6 nCr 1+6 nCr 0) / 2^6 =63/64
