Quality and Reliability Methods - SAS

258 Lifetime Distribution II Chapter 14
Using the Custom Relationship for Fit Life by X
Figure 14.19 Weibull Acceleration Factor Profiler for Devalt.jmp
Using the Custom Relationship for Fit Life by X
If you want to use a custom transformation to model the relationship between the lifetime event and the
accelerating factor, use the Custom option. This option is found in the drop-down menu under
Relationship in the launch window. Comma delimited values are entered into the entry fields for the
location (μ) and scale (σ) parameters.
For example, to create a quadratic model with Log(Temp) for the Weibull location parameter and a
log-linear model with Log(Temp) for the Weibull scale parameter, follow these steps:
1. Open the Devalt.jmp sample data table.
2. Select Analyze > Reliability and Survival > Fit Life by X.
3. Select Hours as Y, Time to Event, Temp as X, Censor as Censor, and Weight as Freq.
4. Select Custom as the Relationship from the drop-down menu.
5. In the entry field for μ, enter 1, log(:Temp), log(:Temp)^2.
(The 1 indicates that an intercept is included in the model.)
6. In the entry field for σ, enter 1, log(:Temp).
7. Click the check box for Use Exponential Link.
8. Select Weibull as the Distribution.
Figure 14.20 shows the completed launch window using the Custom option.