The number of phone calls coming into a switchboard in the next five minutes will either be 0, 1, 2, 3, 4, 5, or 6.The probabilities are the same for each of these (1/7).If X is the number of calls arriving in a five-minute time period, what is the mean of X?
A)2
B)3
C)4
D)5

Question

Quizplus · Accepted Answer

To find the mean, we need to multiply each possible value of X by its probability of occurring, and then add up those products.

So, the mean of X can be calculated as follows:

E(X) = (0)(1/7) + (1)(1/7) + (2)(1/7) + (3)(1/7) + (4)(1/7) + (5)(1/7) + (6)(1/7)

E(X) = 3

Therefore, the mean of X is 3, which is option B

The Number of Phone Calls Coming into a Switchboard in the Next