A company that receives the majority of its orders by telephone conducted a study to determine how long customers were willing to wait on hold before ordering a product. The length of waiting
Time was found to be a variable best approximated by an exponential distribution with a mean
Length of waiting time equal to 3 minutes (i.e. the mean number of calls answered in a minute is
1/3). What proportion of customers having to hold more than 4.5 minutes will hang up before
Placing an order?
A) 0.22313
B) 0.48658
C) 0.51342
D) 0.77687

Question

Quizplus · Accepted Answer

The proportion of customers having to hold more than 4.5 minutes is given by the cumulative distribution function of the exponential distribution with mean 3 minutes, evaluated at 4.5 minutes. This is equal to 1 - exp(-4.5/3) = 0.22313.

A Company That Receives the Majority of Its Orders by Telephone