Written by on Friday January 10th 2014 in SIMUL8 Tips, Technical Corner

SIMUL8 Tip – A quick guide to Stat::Fit

Stat::Fit is a plug-in for SIMUL8 Professional. It is a simple way of knowing which distributions will work best throughout your simulation. This is done by copying raw data into the software then simply auto fitting it to appropriate distributions. Once you have this information you can input it into SIMUL8 and fill in the parameters with the recommended values.

In this example I am going to take the raw data that I have for Inter-arrival times and input this into Stat::Fit to find out the correct distribution to use on my Start Point.

Inter arrival times

Here my data is in a Microsoft Excel format but other applications such as Notepad could also be used.

1.    Select all numerical values for the data you are using and copy these
2.    Open Stat::Fit from within SIMUL8 under the advanced tab
3.    Right-click on the data table and select paste

Data Tables
4.    Click AUTOFIT on the toolbar and select UNBOUNDED in the second box then click OK
5.    You should now see acceptable distributions

Automatic Fitting
6.    In this case I would choose a Normal Distribution because it has been ranked the highest but if I felt something like a Lognormal distribution was more appropriate there is not enough evidence from this small dataset to suggest this is wrong so could equally choose this
7.   By clicking the Graph Fit button I can also see what any of my possible distributions look like compared to my data
Image 4

Image 5

8. As I have chosen a normal distribution I just enter this into my start point in SIMUL8 with the parameters shown of Average 14.7 and standard deviation of 7.55