Suppose X has a binomial distribution 
B 6, 21 Show that  X = 3 is the most
likely outcome (Hint : P(X = 3) is the maximum among all P(xi), xi = 0,1,2,3,4,5,6)
9 On a multiple choice examination with three possible answers for each of the
five questions, what is the probability that a candidate would get four or more
correct answers just by guessing