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Jun 23, 2011

Visualize Reliability Distribution Models

This script presents many distributions that are used to model life data in a reliability or survival analysis. Most of them are available in the Life Distribution platform (Analyze > Reliability and Survival > Life Distribution).

Simply run the script to begin. The four important distribution functions are presented in separate plots of the graph of each function: Failure (CDF), Survival (1-CDF), PDF, and Hazard. The initial choice is the normal distribution. Other distributions may be selected by clicking a radio button on the right side. The parameters of the distribution may be changed by moving a slide or entering the number directly. The functions are also displayed in the lower right of the window.

(Note that some of the hazard functions do not have an explicit form. The general form of PDF / (1-CDF) can lead to numerical instability that is evident in the plot of the graph of the hazard function.)


For me the script was already extremely useful to visualize different scenarios in survival studies dependent on assumptions on survival distributions and their parameters. Distributions can be selected and parameters modified in a very userfriendly way.

My wishes for further development would be:

- Visualize data situations where the observations are a mixture of two groups with different distributions; mixture percentages chosen by the user,

- Plot several scenarios into one figure to support comparability.

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