Question

Assume that emergency medical personnel in California are planning for future resources and it has been observed that the average number of traffic accidents requiring ambulance assistance on the Hollywood Freeway between 7 and 8 AM on Wednesday mornings is 1.1. What, then, is the probability that there need for exactly 2 ambulances on the Freeway during that time slot on any given Wednesday morning?

Answer 1

Answer is 0.5

Explanation:

The text implies that the number of traffic accidents determines the number of ambulances required on the road. Hence, 1 traffic accident requires 1 ambulance.

The time slot and time of day remain same in both the text and the question.

The average or mean number of accidents is 1.1

QUESTION: What then is the probability that there is need for exactly 2 ambulances on that road and in that time frame?

In other words, what is the probability that there'll be 2 accidents on that road and in that time frame?

Since the mean number of accidents is 1.1, 2 is above the mean.

Probability of 1.1 accidents is 1, since that's the mean (expected value).

Probability of 2 accidents is 1/2 which is = 0.5