The waiting times on hold for a call to a customer service department are observed to have the following probability distribution: Number of calls, x Waiting time, minutes, f(x)
0 0
2 3
4 10
6 15
8 10
10 6

The expected value of the waiting time for a random call is most nearly:

a. 7.3 minutes
b. 9.2 minutes
c. 11.5 minutes
d. 15.0 minutes

b. 9.2 minutes

Step-by-step explanation:

To find the expected waiting time for a random call from the sampie given by using the formula:

number of calls (x)           waiting time f(x) in minutes         f(x) *(x)

0                                                     0                                         0            

2                                                     3                                         6

4                                                     10                                       40

6                                                     15                                       90  

8                                                     10                                       80

10                                                     6                                       60  

Therefore:

2 over 5

step-by-step explanation:

the 2: 3 ratio is the length of the ac segment to the cb segment total length. this implies that the ratio between segment ac length and segment ab length is 2: 5. point c is 2/5 from a to b, so the required fraction is 2/5.