Question

Probability distribution

Answer 1

a) The value of q is 0.2.

b) E(X) = 1.85.

Explanation:

Question a:

The sum of all the probabilities must be 1. So

`0.3 + x + 0.1 + 0.15 + 0.25 = 1`

`x + 0.8 = 1`

`x = 0.2`

The value of q is 0.2.

Question b:

Multiplication of each value of x by its probability. So

`E(X) = 0*0.3 + 1*0.2 + 2*0.1 + 3*0.15 + 4*0.25 = 1.85`

So the answer is E(X) = 1.85.