Fitting Discrete Distributions

Select the Discrete Distributions option button and any discrete distribution type from the Distribution Fitting Startup Panel , and click OK to display the Fitting Discrete Distributions dialog box, which contains three tabs: Quick, Parameters, and Options.

Note that additional specialized distributions can also be estimated (fit to data) using Survival Analysis. Survival Analysis is particularly useful for fitting the Weibull and Gompertz distributions, which are widely used for modeling survival or failure times, and is also specifically "equipped" to handle censored data, that is, data that are incomplete.

Distribution. The Distribution box is available only after a variable has been selected. Use the Distribution box to select the discrete distribution type you want to fit. Note that the distribution selection is automatically set to match the discrete distribution type you selected on the Distribution Fitting Startup Panel, but you can change the distribution here if you want.

Variable. Click the Variable button to display a standard variable selection dialog box, in which you can select the variable you want STATISTICA to analyze. After you select the variable, you can then change the distribution and parameters on their respective tabs.

Summary. Click the Summary button to display either the standard variable selection dialog box, or the analysis of the observed and expected distribution (if a variable has already been selected).

Cancel. Click the Cancel button to return to the Distribution Fitting Startup Panel.

Options. Click the Options button to display the Options menu.

By Group.  Click the By Group button to display the By Group specification dialog box.

Select Cases. Click the Select Cases button to display the Analysis/Graph Case Selection Conditions dialog box, which contains options to create conditions for which cases will be included (or excluded) in the current analysis. More information is available in the case selection conditions overview, syntax summary, and dialog box description.

W. Click the W (Weight) button to display the Analysis/Graph Case Weights dialog box, which contains options to adjust the contribution of individual cases to the outcome of the current analysis by "weighting" those cases in proportion to the values of a selected variable.