A and B are independent events. Which equation below must be true?

A. P (A) = P (B)

B. P (A | B) = P (A)

C. P (A ∩ B) = P (A)

D. P (B) = P (A | B)

The correct answer for this question is B. P (A | B) = P (A). Another equation used for independent events is P (B | A) = P (B). When the multiplication rule is applied, this gives an alternative definition of independence which is:

P (A ∩ B) = P (A) * P (B)

Independent events are events that can occur without affecting or changing the probability of the other.