The Regression with Life Data is used to assess whether predictors affect failure time and ultimately develop a model that can be used to predict failure time. The model can include single factor, single covariate, interaction terms and nested terms.
You can use ProcessMA Regression with Life Data to model uncensored/right censored data with one of the seven distributions (Weibull, Exponential, Normal, Lognormal, Logistic, Loglogistic, Smallest Extreme Value).
ProcessMA uses maximum likelihood estimates to model parameters.
At the Excel Menu (For Excel 2007, go to Add-ins first)
Choose ProcessMA > Reliability and Survival > Regression with Life Data
In Response, select the column containing the response data
In Term 1 to Term 10 , select the column containing data for the respective model terms and choose if the term is a covariate or a factor (Covariate: Numeric)
In Model, enter the terms to be included in the model. The Model can include factors, covariates, interactions and nested term. Multiple terms must be separated by commas. Use * to represent interactions and () to represent nesting. The model must be hierachical, if an interaction term is included, all lower order interactions and main terms must also be included.
In Assumed Distribution, choose the distribution to fit
In Censor, select the column containing censoring indicator (Optional, Exactly 2 distinct values - censored and uncensored)
In Censor Value, choose the indicator you use to indicate censoring
Check Standardized Residuals, if you want to display a probability plot for standardized residuals
Check Cox-Snell Residuals, if you want to display a probability plot for Cox-Snell residuals
Check Show Confidence Interval, if you want to display confidence interval in the above plots
In Confidence Level, enter the desired confidence level (Numeric, >0 & <1)
Click OK
You work in a manufacturing plant making widgets and you want to find out the deterioration of widgets. You want to know if you can predict failure times for widgets based on the temperature and the chamber it operates in. It is known that the relationship between temperature and failure time follows the Arrhenius relationship.
Open data worksheet by choosing ProcessMA > Tools > Data
Choose ProcessMA > Reliability and Survival > Regression with Life Data
In Response, select CL - Times2
In Term 1, select BN - Temp2 and choose Covariate
In Term 2, select BO - Chamber and choose Factor
In Model, enter Temp2, Chamber
In Assumed Distribution, choose Weibull
Under Censor Tab, in Censor, select CM - Cen2
Under Censor Tab, in Censor Value, choose C
Click OK
From the regression table, you can obtain the coefficients for the regression model.
Copyright © ProcessMA