Question

I operate a small convenience store. Typically, I get about 10 customers per hour. If the mean time before I get my 25th customer is 2.5 hours, what is the standard deviation associated with the time until I see my 25th customer

Answer 1

The standard deviation associated with the time until I see my 25th customer is of 2.5 hours.

Explanation:

In this problem, we have the mean time between x successes, which characterizes the exponential distribution.

As in this question context, the important thing to note is that for the exponential distribution, the mean and the standard deviation are the same.

Mean time before I get my 25th customer is 2.5 hours, what is the standard deviation associated with the time until I see my 25th customer?

They are the same in the exponential distribution, so 2.5 hours.