Windchill Risk and Reliability Desktop Help > Windchill Weibull > Test Planning Calculator > Test Planning Calculator How-Tos > Using the Chi-Square Distribution to Compute Accumulated Test Time
Using the Chi-Square Distribution to Compute Accumulated Test Time
You can use the Test Planning Calculator and the Chi-Square distribution to compute accumulated test time.
1. If the Test Planning Calculator is not already open, select LDA > Test Planning to open it.
2. In the navigation pane, click Chi-Square.
3. Under Parameters, do the following:
a. For Demonstration type, select Reliability, MTBF, or LX to indicate the known parameter.
This last type is the age at which X percent of the population is expected to fail.
Based on the selection you make in this field, the label for the next field changes.
b. Enter the parameter values for the chosen demonstration type. For more information, see Chi-Square Parameters.
4. When finished, click Calculate. The result for accumulated test time is shown in a display-only field under Result.