A company that receives most 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 .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 will hang up before placing an order is given by the cumulative distribution function of the exponential distribution with a mean length of waiting time equal to 3 minutes, evaluated at 4.5 minutes. This is equal to 1 - exp(-4.5/3) = 0.22313.

A Company That Receives Most of Its Orders by Telephone