If p(e)= 0.55, p(e or f) =0.85 and p(e and f) =0.05 find p(f)

Question

Statistics

Answer 1

You can use a Venn Diagram to work this out.

You can also use the equation P(e or f) = P(e) + P(f) - P(e and f)

Therefore, P(f) = P(e or f) - P(e) + P(e and f) (It's a good idea show both of these equations for a Venn Diagram)