Answer:
0.25 or 25% probability
Explanation:
The lower limit in this question = a
The upper limit = b
P(X<=x) = x-a/b-a
a = 4
b = 8
The question says it is uniformly distributed between 4 minutes and 8 minutes
Probability that it takes her more than 7 minutes to wait for the bus
P(X<=7) + P(X>7)= 1
We are to get P(X>7)
= 1 - (7-4/8-4)
= 1-3/4
= 1-0.75
= 0.25
= 25% probability it takes her more than 7 minutes to wait