probailty question (ANOTHER)3.Suppose that a discrete random variable X assumes values from the set SX = {0,1,2,…,8}.Suppose that the pmf of X has the form,px(k) = a*k for k=0,1,2,...,8and zero otherwise.(a) Find the value of a .(b) Find the probability that {X ≤ 4}.
问题描述：
probailty question (ANOTHER)
3.Suppose that a discrete random variable X assumes values from the set SX = {0,1,2,…,8}.
Suppose that the pmf of X has the form,
px(k) = a*k for k=0,1,2,...,8
and zero otherwise.
(a) Find the value of a .
(b) Find the probability that {X ≤ 4}.
答
(a)：∑px(k) = 1,即px(0)+px(1)+...+px(8) = 1,解得 a = 1/36
(b)：