Quality and Reliability Methods - SAS

Chapter 13 Lifetime Distribution 221
Additional Examples of the Life Distribution Platform
Table 13.1 Comparison Criteria (Continued)
Criterion Formula a Description
AICc
n
AICc = -2loglikelihood + 2k-------------------
n
– k – 1
Corrected Akaike’s Information
Criterion
AICc = AIC
+ ---------------------- 2k( k+
1)
n – k – 1
a. k =The number of estimated parameters in the model; n = The number of observations in the data set.
For all three criteria, models with smaller values are better. The comparison criterion that you select should
be based on knowledge of the data as well as personal preference. Burnham and Anderson (2004) and
Akaike (1974) discuss using AICc and BIC for model selection.
Additional Examples of the Life Distribution Platform
This section includes examples of omitting competing causes and changing the distribution scale.
Omit Competing Causes
This example illustrates how to decide on the best fit for competing causes.
1. Open the Blenders.jmp sample data table.
2. Select Analyze > Reliability and Survival > Life Distribution.
3. Select Time Cycles and click Y, Time to Event.
4. Select Causes and click Failure Cause.
5. Select Censor and click Censor.
6. Select Individual Best as the Distribution.
7. Make sure that AICc is the Comparison Criterion.
8. Click OK.
On the Competing Cause report, JMP shows the best distribution fit for each failure cause.