Fit Distributions - Continuous Variables Tab
Select the Continuous variables tab of the Fit Distributions dialog box to access the options described here.
<< Prev./Next >>
When more than one continuous variable is selected for the analysis, you can switch between them via the << Prev. and Next >> buttons (or use the adjacent drop-down menu). The specifications for each variable are unique, i.e., all selected distributions only apply to the current variable, and different variables can have different specifications.
Distribution
Select one or more continuous distributions to fit to your selected continuous variables.
Normal
Select the Normal check box to fit the Normal distribution to the currently selected variable.
Log-Normal
Select the Log-Normal check box to fit the Log-Normal distribution to the currently selected variable.
Folded normal
Select the Folded normal check box to fit the Folded normal distribution to the currently selected variable.
Half normal
Select the Half normal check box to fit the Half normal distribution to the currently selected variable.
Rayleigh
Select the Rayleigh check box to fit the Rayleigh normal distribution to the currently selected variable.
Weibull
Select the Weibull check box to fit the Weibull distribution to the currently selected variable.
Gaussian mixture
Select the Gaussian mixture check box to fit the Gaussian Mixture distribution to the currently selected variable.
Johnson distribution (general non-normal single mode)
Select the Johnson distribution (general non-normal single mode) check box to fit the Johnson distribution (general non-normal single mode) distribution to the currently selected variable.
Percentile Fit
By default, the Johnson distribution is fitted by moments (for details see Hahn and Shapiro, 1967, pages 199-220; and Hill, Hill, and Holder, 1976). Select this checkbox to estimate the parameters of the Johnson distribution via the percentile based method outlined in Chou, Polansky, and Mason.
Generalized Extreme Value
Select the Generalized Extreme Value check box to fit the Generalized Extreme Value distribution to the currently selected variable.
Generalized Pareto
Select the Generalized Pareto check box to fit the Generalized Pareto distribution to the currently selected variable.
Triangular
Select the Triangular check box to fit the Triangular distribution to the currently selected variable.
Offset (threshold/location)
Some distributions have particular valid value ranges (e.g., for Weibull the observed values must be greater than zero). For those distributions, you can specify a lower threshold (location) value. The threshold (location) values will be subtracted from the observed values before the respective distribution is fitted.