A travel agency wants to describe the time between incoming telephone calls when the calls are averaging about 35 every 10 minutes. This same example was used for the Poisson distribution to describe the number of calls arriving every 10 minutes.
The first step in selecting a probability distribution is matching the data with a distribution’s conditions. Checking the exponential distribution:
The conditions in this example match those of the exponential distribution.
The exponential distribution has only one parameter: rate. The conditions outlined in this example include the value for this parameter: 35 (calls) every 10 minutes or a rate of 35. Enter this value to set the parameter of the exponential distribution in Crystal Ball.
The distribution in Figure 99, Exponential Distribution shows the probability that x number of time units (10 minutes in this case) will pass between calls.
