For the sample space {a, b, c} P(a) = 0.4, P(b) = 0.2, P(c) = 0.5. Is this a valid probability assignment?

Question

a. Valid

b. not valid

Answer 1

 

The sum of probabilities is always equal to 1 .

P(a) + P(b) +P(c) = 1 . 

0.4 + 0.2 + 0.5 = 1.1 

1.1 not equal to 1 .

So the probability is not valid .

Therfore  option (b) is correct .