Fit Distributions to Data

The Fit Distributions to Data window allows the configuration of the fitting process to an existing set of data. Once a distribution function has been fit to a data set, that function can be added to a model as an Input for use during simulations. The Fit Distributions to Data window has five tabs:

Data - Define the data set to be included in the fitting, as well as the data type and any filters to be applied.
Distributions - Define which distributions should be tested for fitting, as well as options for how to perform the fitting.
Bootstrap - Include Parametric Bootstrapping in the fitting process; see Fit Bootstrap for more information.
Chi-Sq Binning - Configure the binning for the data set when running chi-squared testing; see Chi-Squared Binning for more information.
Results - Configure the fitting method @RISK will utilize when measuring how well a distribution fits to the data set. Also includes options for reporting fits when performing Batch Fitting.

Figure 1 - Fit Output

Data from a simulation Output can also be used as the source data for fitting. To fit distributions to simulated data, click the Settings/Actions button in the Browse Results window and select 'Fit Output' (Figure 1, right).

Define Fit Command Buttons

For both the Fit Distributions to Data window (single fitting mode) and Batch Fit window (batch fitting mode), the Command Buttons contain the following options:

Help - Open help resources (online or local, based on @RISK settings); see Help Button for more information.
Settings/Actions - Window-specific settings and actions. The Fit and Batch Fit options are:
- Delete Fit - For an existing fit, delete its definition from the worksheet.
- Set as Defaults - Set the currently configured Fit options as the default values; this setting is applied to the application and will persist between workbooks.
- Reset to Defaults - Reset the current configuration to the @RISK defaults or the user-defined defaults, if those defaults have been set.