State which of the following are not the probability distributions of a random variable. Give reasons for your answer.
(i)
x 0 1 2
P(X) 0.4 0.4 0.2
(ii)
x 0 1 2 3 4
P(X) 0.1 0.5 0.2 -0.1 0.3
(iii)
y -1 0 1
P(y) 0.6 0.1 0.2
(iv)
z 3 3 1 0 -1
P(z) 0.3 0.2 0.4 0.1 0.05
Select the correct answer from above options