Answer:
B. Of the students who walk, the probability of choosing a female.
D. Of the females, the probability of choosing one who rides the bus.
Step-by-step explanation:
Conditional probability is the chance of something happening provided that something else has previously occured (think dependent events).
For example, the probability of getting into college P(college) is Event A.
The probability of receiving dormitory housing P(housing) is Event B.
First, the person must get into college before they are even able to receive dormitory housing. Therefore, this is a situation of conditional probability. The "condition" of being accepted into the college (Event A) is necessary before the individual can attempt Event B, housing.
The key word in the question is "Of all the students." This means that from the first instance, you are only calculating one probability.
However, in B, it first singles out "all the students who walk."
Therefore p(walk) must be met before p(gender) can happen.
Same with D, it singles out "of the females."
Therefore p(gender) must be met before p(transportation) can happen.
C does have two categories, but since it is still out of the general draw pool "of all students," it is not conditional. No condition needs to be met first to choose a male who walks out of ALL students.