Question

The probability that Edward purchases a video game from a store is 0.67 (event A), and the probability that Greg purchases a video game from the store is 0.74 (event B). The probability that Edward purchases a video game (given that Greg has purchased a video game) is 0.67. Which statement is true?
A. Events A and B are independent because P(A|B) = P(A)
B. Events A and B are dependent because P(A|B) = P(A)
C. Events A and B are independent because P(A|B) = P(B)
D. Events A and B are dependent because P(A|B) P(A)

Answer 1

Events A and B are independent because P(A|B) = P(A).

Given two events A and B, the conditional probability P(A|B) is the probability that A happends, knowing that B has happened. If the two events are dependent, knowing that B has already happened will change the probability of A. If, instead, knowing that B has happened doesn't change the probability of A, it means that A doesn't depend on B, and thus the events are independent.