Splicing Distributions | Vose Software

Splicing Distributions

See also: ModelRisk functions and windows, Distributions in ModelRisk, Common elements of ModelRisk windows


The Splicing distributions window allows one to connect the left part of a given distribution together with the right part of another distribution, at a point (the so-called splice point) of one's choice.

This is typically used for modeling a variable that follows a certain distribution for in the lower x region, but has a longer tail.

Splicing distributions is explained in more detail here.

To see the output functions of this window, click here.

Window elements

In the Splice parameters region on the left, you can specify the distributions and the splice point.

In the LowDistribution field comes the distribution object that will constitute the 'left' part (i.e. the lower x-value), in the HighDistribution field comes the distribution object that will constitute the 'right' part (i.e. the higher x-values). You can provide the Splice Point as well.

For this calculation to make sense, the lower and higher distributions should have a region of overlap, and the splice point should be in this region.

The graph is showing you the spliced distribution you constructed together with a vertical bar, allowing you to move the splice point manually along the graph.  

Different types of output can be specified by selecting the appropriate option under the preview graph:

  • Object - to insert the constructed distribution as a distribution Object in the spreadsheet.

  • Simulation - (default) to generate random values from the distribution.

  • f(x) and F(x) - to calculate the probability density function and the cumulative distribution function of some x value(s) (an extra parameter x values will appear on the left side of the window).

  • F-1(U) - to calculate the inverse cumulative when a U-value is entered.

For explanations about other fields, buttons, graphs and summary statistics tables in this window, see Common elements of ModelRisk windows.

Useful tips and tricks

See also: Graphics, workflow and error handling in ModelRisk

Using View Function to return to a window

The output of ModelRisk windows always corresponds to VoseFunctions (the functions ModelRisk adds to Excel) being entered into one or more spreadsheet cells.

You can always re-open the window for a ModelRisk function that is in a spreadsheet cell by using View Function. Select the spreadsheet cell and then select View Function from the ModelRisk menu/toolbar/ribbon.