75.2k views
2 votes
Event B is dependent on event A, and event A occurs before event B. Which expression is equal to the probability of event A?

A. P(B|A)
B. P(B)
C. P(A ∩ B)
D. P(A) × P(B|A)
E. P(A) × P(B)"

User Filiprem
by
6.7k points

1 Answer

3 votes

Final answer:

The correct expression that represents the probability of event A, when event B is dependent on it, is P(A). This is because it represents the chance of event A occurring independently of event B.

Step-by-step explanation:

The student's question relates to the probability of event A when event B is dependent on event A. Given that event B is dependent on event A and event A occurs before event B, the expression that is equal to the probability of event A is simply P(A). The other expressions listed, such as P(B|A), P(B), P(A ∩ B), and P(A) × P(B), are related to event B or the joint probability of A and B.

None of those expressions directly provide the probability of event A alone. Hence, the correct answer is D. P(A). This is because P(A) represents the probability of event A occurring on its own without any consideration of event B. In contrast, P(B|A) would represent the probability of event B occurring given that event A has already occurred. The Multiplication Rule, P(A AND B) = P(A) × P(B|A), is used to find the joint probability of both events A and B happening, which is not what we are asked to find here.

User Cote Mounyo
by
8.4k points