Suppose the waiting time in a Piggly Wiggly checkout line follows an Exponential distribution with an average wait of 7 minutes. What is the 80th percentile of waiting times?

11.3 minutes

Step-by-step explanation: Exponential Distribution is a distribution with function of the form:

often related to an amount of time until an event occur.

The greek letter λ is decay parameter and have a relationship with the mean:

and x is the amount of time

Probability in exponential distribution is given by

Percentile is a value below which a percentage of the data falls.

For the waiting line in a Piggly Wiggly checkout, 80th percentile will be

h = 11.3

The 80th percentile of waiting times is 11.3 minutes.