Question

The following frequency distribution gives the response times of EMTs after dialing 911. Assume that each value in a class is equal to the midpoint of the class. Estimate the mean response time for the given data. Round your answer to the nearest hundredth.

Response Times of EMTs (In Minutes)

Class	Frequency
5.50–6.49	25
6.50–7.49	56
7.50–8.49	17
8.50–9.49	40
9.50–10.49	45

Answer 1

First, we need to find the midpoint for each class

Midpoint = (Upper limit + lower limit)/2

5.50–6.49	(6.49+5.50)/2 = 5.995
6.50–7.49	(7.49+6.50)/2 = 6.995
7.50–8.49	(8.49+7.50)/2 = 7.995
8.50–9.49	(9.49+8.50)/2 = 8.995
9.50–10.49	(10.49+9.50)/2 = 9.995

Calculation for mean

Hence, mean = 8.13 minutes