Question

If p(a)=.78 and p(b)=.66 and p(a and b)= .53 what is p(a or b)

Answer 1

0.91.

Explanation:

We use the formula:

P(a U b) = p(a) + p(b) - p (a ∩ b) where P(a U b) is p(a or b) and p (a ∩ b) is p (a and b).

So p(a or b) = 0.78 + 0.66 - 0.53

= 0.91.