Question

The following mass function describes the distribution for a random variable x:

p(x)=0. x={1,2,3,...} (the upper bound of x is )

a) What is the probability x=5?

b) What is the probability x ≥ 2?

c) What is the probability x=1.5

Answer 1

The probability mass function (pmf) of X is:

This is an invalid pmf because the sum of the probabilities at all the points is not equal to 1.

This violates the most important property for a pmf to be valid.

Hence, further probabilities cannot be determined using the given pmf.