Some Notes on Diagnostic Procedures in Simple and Multiple Linear Regression Profiles Monitoring

Abstract

Sometimes a relationship between a response variable and one or more explanatory variables known as profile describes the quality of a process. In Phase I, after a control procedure signals the presence of an assignable cause(s), finding the out-of-control samples as well as attributing the shift to model parameters are main objectives. Some diagnostic methods proposed in Phase I analysis of simple and multiple linear profiles. In this article, we modify the procedure by Mahmoud (2008) to improve the method. Moreover, the diagnostic procedure by Mahmoud and Woodall (2004) is discussed. The improvement is illustrated using simulation and numerical examples.

Keywords:

• Control chart
• Diagnosis
• Multiple linear regression profile
• Phase I
• Statistical process control

Mathematics Subject Classification:

• Primary 62J20
• Secondary 62F03

Acknowledgment

The authors gratefully acknowledge Dr. Eyvazian for his comments on the current manuscript. Authors also appreciate precious and valuable comments by the anonymous referees which led to improvement in the article.