In: Statistics and Probability
By rewriting the formula for the multiplication rule, you can write a formula for finding conditional probabilities.
The conditional probability of event B occurring, given that event A has occurred, is Upper P left parenthesis Upper B vertical line Upper A right parenthesis equals StartFraction Upper P left parenthesis Upper A and Upper B right parenthesis Over Upper P left parenthesis Upper A right parenthesis EndFraction . Use the information below to find the probability that a flight departed on time given that it arrives on time.
The probability that an airplane flight departs on time is 0.91.
The probability that a flight arrives on time is 0.86.
The probability that a flight departs and arrives on time is 0.82.
The probability that a flight departed on time given that it arrives on time is 2 nothing. (Round to the nearest thousandth as needed.)
P(flight departed on time | it arrives on time) = P(flight departs and arrives on time) / P(flight arrives on time)
= 0.82 / 0.86
= 0.953