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1. Introduction
Since last few years, the buzzword in quality management is the implementation of the Lean Six Sigma, which has emerged as a convergence of two concepts, i.e. Lean and Six Sigma ([28] Muir, 2006; [31] Smith, 2003). While Lean emphasises on speed and waste, Six Sigma emphasizes on variation, defects and process evaluation ([4] Antony, 2011). An organisation should capitalise on the strengths of both Lean management and Six Sigma for an effective implementation of the Lean Six Sigma ([5] Arnheiter and Maleyeff, 2005). The implementation of the Lean Six Sigma calls for carrying out of improvement projects leading to satisfaction of stakeholders, based on the ideology of [22] Juran (1964). The employees of the organisations responsible for implementation are trained in various belts and they execute projects based on Lean Six Sigma project management methodology, i.e. define-measure-analyse-improve-control (DMAIC) ([17] George, 2002). The business problems are defined and measures are established in the "define phase". In the "measure phase", present performance levels are estimated after taking appropriate corrective actions with regard to the deficient measurement system, if there is any, and subsequently ensuring adequate process stability. In the "analyse phase", principally the root causes are identified and validated after identification of the potential causes. The process of identification of the root cause based on a structured approach is known as the root cause analysis (RCA). The solutions are identified and implemented in the "improve phase" and the sustenance of results is ensured at the "control phase".
In the "analyse phase" the identification of the root cause(s) is generally based on the popular tools like cause and effect diagram (CED), why-why analysis, tree diagram, etc. ([25] Mahto and Kumar, 2008). In order to establish the one-to-one relationship between the causes of a pertinent effect, data are collected and analysed. The analysis generally calls for the usage of various statistical techniques, which may be listed under the broad heading known as the "test of hypothesis".
RCA is one of the most useful themes being used by practitioners around the globe for quite a long time in industrial problem solving on quality and productivity, plant safety, accidents, etc. The theme is continually being developed by the researchers and practitioners. It can be bifurcated into two broad...