Vose probability calculation f(x) F(x) and F-1(U) windows | Vose Software

Vose probability calculation f(x) F(x) and F-1(U) windows

See also: Probability calculations in ModelRisk



The probability calculation windows are accessible through the Vose ModelRisk menu under Probability calculation.

With these windows you can calculate respectively the joint probability density (or probability mass) f({x}) and joint cumulative probability F({x}) for a set of values {x} against a specified distribution.

These windows offer a simple way of calculating the likelihood of observations being drawn from a specified distribution, which is useful for various statistical models from distribution fitting to hypothesis testing, as well as predicting the likelihood of observing values in the future.   

There are three windows for probability calculations in ModelRisk:

The ModelRisk functions for probability calculations are VoseDistribution (with a U-parameter),VoseDistributionProb and VoseDistributionProb10.These are explained in depth here.

Window elements

In the Distribution drop-down menu you can choose the distribution to perform the probability calculation on. In the parameters region below you can specify the distribution's parameters (or link them to a spreadsheet cell).

In the shift distribution field, you can provide the amount the distribution should be shifted along the X-axis. By default this is zero.

In the bounds region you can specify whether the distribution is truncated at certain x-values (Xbounds) or at certain percentile values (Pbounds).

In the x values fields you can insert the x values of which the (joint) probability or likelihood is to be calculated. By marking the Log 10 checkbox the logarithm (base 10) of the joint probability is calculated.

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.