One feature that sets FlexSim apart from other simulation tools is the ability to quickly and easily build a little bit of variability and randomness into your simulation model. FlexSim gives you the ability to simulate many kinds of fluctuations in your business system. Fortunately, you don't need to know a lot of complicated mathematics or programming to create these mathematical expressions. FlexSim has a tool called the Distribution Chooser that will help you select an appropriate statistical distribution to randomly calculate any kind of randomness. When you're done using the Distribution Chooser, it will create a mathematical expression based on the options you selected and it will automatically apply it to the daily demand or process times settings. (See Using the Distribution Chooser for more information.)
The Distribution Chooser is shown in the following image:
The Distribution Chooser allows you to select from thirty possible statistical distributions to generate random numbers. Some of the most commonly used distributions are:
- Exponential - Will randomly select most numbers near the beginning of a range of numbers. The frequency that numbers near the end of the scale will be generated decreases exponentially. This is the default distribution strategy because it is the distribution strategy most commonly found in the real world.
- Duniform - Will randomly select any whole numbers within a specific range. If you want to be able to include numbers with decimal points, use the Uniform distribution strategy instead.
- Normal - Has a distribution strategy similar to a bell curve in which numbers in the middle of the distribution scale are more likely to be generated at random.
- Triangular - Similar to the normal distribution strategy, but has a greater range of numbers in the middle of the distribution scale that are more likely to be generated at random.
- Uniform - Will randomly select any numbers within a specific range. The Uniform distribution strategy will include numbers with decimal points. If you'd rather only create whole numbers, use the Duniform distribution strategy instead.
You can change the settings for each statistical distribution so that it uses different criteria or ranges of numbers to generate the random numbers. When you make changes to the settings, the blue bar graph will update to display the probabilities that certain numbers will be generated.
Learning About the Other Distributions
Consider looking up some of the other statistical distributions in a book about statistics to learn more about them. FlexSim's ExpertFit tool can also help you decide on an appropriate distribution strategy using historical data or data gathered from a time study.
