When an ALT data set is selected in the LDA Navigator, Fixed? checkboxes appear below Calculation results in its ALT Parameters pane. These checkboxes indicate whether parameter values are calculated or specified. Typically, a parameter’s Fixed? checkbox is cleared, which indicates that the value is calculated. Once the data set is calculated, the value computed for the parameter replaces the number signs (#.#) that initially appear in the display-only field to its right. To specify the value to use for a parameter, you select its Fixed? checkbox, which makes the field to its right available. In it, you enter the value to use.

The following table lists the shape parameter that can be fixed for either the Weibull or lognormal distribution. Because the exponential distribution always has the same shape, no shape parameter is calculated or specified for it. You can fix values for the life stress model’s parameters. For more information, see Life Stress Model Parameters.

While the last value under Calculation results is Log likelihood, it is not a parameter. It is a statistical measure for the MLE (maximum likelihood estimation) method that indicates how closely the distribution “fits” the data.

Parameter results are shown below Calculation results in the ALT Parameters pane. Additionally, they are shown in the ALT Results pane. For more information, see ALT Results Pane for an ALT Data Set.