On a given day, 280 people jaywalk across a busy intersection.Of these people, 50% are male, 80% are university undergraduate students, and 40% are female university undergraduate students.A person is hit by a car while jaywalking across the intersection.We can see that the person is female.What is the probability that the victim is a university undergraduate student?
A) 0.40
B) 0.32
C) 0.10
D) 0.80

Question

Quizplus · Accepted Answer

Given that 40% of the people jaywalking are female university undergraduate students, and since we know the victim is female, the probability that she is a university undergraduate student is 40% or 0.40. However, the correct interpretation of the given information leads to the understanding that 40% of the total jaywalkers are not female undergraduates, but rather that 40% of the females are undergraduates. Since 50% of the 280 people are female, this means 140 are female, and 40% of these females are undergraduates. Therefore, if the victim is known to be female, the probability she is an undergraduate is 40% of the females, not of the total population, which correctly interpreted is 100% or 1.0 for the given choices, indicating a mistake in the initial answer selection.

On a Given Day, 280 People Jaywalk Across a Busy