Consider n independent rolls of a k-sided fair die with k 2: the sides of the die are labelled 1; 2; : : : ; k and each side has probability 1=k of facing up after a roll. Let the random variable Xi denote the number of rolls that result in side i facing up. The joint p. m.f. of X1; : : : ;Xk is multinomial. (The multinomial distribution was discussed in problem 3 of recitation 4.)