This example uses the sample data table, from Meeker and Escobar (1998), and can be found in the Reliability folder of the sample data. It contains time-to-failure data for a device at accelerated operating temperatures. No time-to-failure observation is recorded for the normal operating temperature of 10 degrees Celsius; all other observations are shown as time-to-failure or censored values at accelerated temperature levels of 40, 60, and 80 degrees Celsius.
Open the sample data table.
Select Analyze > Reliability and Survival > Fit Life by X.
Select Hours and clickY, Time to Event.
Select Temp and click X.
Select Censor and click Censor.
Leave the Censor Code as 1.
Select Weight and click Freq.
Keep Arrhenius Celsius as the relationship, and keep the Nested Model Tests option selected.
Select Weibull as the distribution.
Keep Wald as the confidence interval method.
Fit Life by X Launch Window shows the completed launch window.
Fit Life by X Launch Window
Click OK.
Fit Life by X Report Window for Data shows the top half of the Fit Life by X report window.
Note: A message might appear stating that “Analysis must exclude groups that are all right censored to continue Nested Model Tests. Do you want to continue?” Click Yes to continue the analysis. Right censored groups indicate groups where all observations are right censored. In this example, group Temp = 10 has only one row, is considered to be right censored, and has to be excluded to allow the Nested Model Test. The message does not appear if your sample data does not include right censored observations.
Fit Life by X Report Window for Data