# Joint Property Statistics

If you are using the Probabilistic Analysis option, you can define joint property statistics (random variables) with the Joint Properties option in the Statistics menu.

## Joint Properties

Before you can define joint property statistics, you must first define your basic joint properties (e.g. slip criterion) in the Define Joint Properties dialog.

This will ensure that the appropriate random variables are available in the Joint Property Statistics dialog, as described below.

## Joint Property Statistics

To define joint property statistics:

1. Select Joint Properties from the Statistics menu.
2. Select a joint material from the list at the left of the Joint Property Statistics dialog.
3. Select the Add button for each random variable you would like to define. Each time you select the Add button, a new random variable will be added to the list of random variables. NOTE:
• If you repeatedly select the Add button, you will see ALL possible random variables that can be defined for that joint material. You can then use the Delete button to remove variables from the list if necessary.
• Alternatively, you can select the Add button once for each required variable. Then click on the Property name and you will see a drop-list of all possible random variables, from which you can choose a desired variable.
4. For each random variable, enter the required input parameters.
• If you are using the Monte Carlo or Latin Hypercube sampling methods, then you can choose a statistical distribution for the variable, and enter the Mean, Standard Deviation (if applicable) and Relative Min and Max values.
• If you are using the Point Estimate Method, then only the Mean and Standard Deviation is required for each random variable.

NOTE:

• If the desired random variables appear to be missing from the list of available variables, then make sure that you have correctly chosen the basic joint properties in the Define Joint Properties dialog. For example, if strength parameters are not available as random variables, then make sure that you have chosen the correct slip criterion. If Slip Criterion = None in Define Joint Properties, then the strength property random variables (e.g. cohesion and friction angle) will NOT be available in the Joint Property Statistics dialog.
• Not all joint properties can be defined as random variables. If a variable does NOT appear in the Joint Property Statistics dialog, regardless of the properties chosen in the Define Joint Properties dialog, then this indicates that the variable cannot be defined as random for the probabilistic analysis.