Question

Events A and B have probabilities such that P(A) = 0.3, P(B) = 0.25, P(M ∪ N) = 0.425, and P(M ∩ N) = 0.075. Are events A and event B independent? (I think is the middle one)

Question options:

Yes, because P(M) - P(N) = P(M ∩ N)
Yes, because P(M) ∙ P(N) ≠ P(M ∩ N)
Yes, because P(M) ∙ P(N) = P(M ∩ N)
No, because P(M) + P(N) = P(M ∪ N)
No, because P(M) ∙ P(N) ≠ P(M ∪ N)

Answer 1

(C)Yes, because P(M) ∙ P(N) = P(M ∩ N)

Explanation:

Two events A and B are independent if P(A)P(B)=P(A ∩ B)

Given events A and B such that:

P(A) = 0.3, P(B) = 0.25, P(A ∪ B) = 0.425, and P(A ∩ B) = 0.075

• P(A)P(B)=0.3 X 0.25 =0.075
• P(A ∩ B) = 0.075

Since the two expression above gives the same answer, they are independent.

The correct option is C.