Sabbyasachi Muakherjee

Z is the process sigma score between the sample mean and the specification limit of the process. So, while going into the Measure phase of the DMAIC, it is must for a Six Sigma professional to have a Sigma Level score and then they would compare the same with the Sigma Level Score during the Implementation phase of the DMAIC. The comparison between the scores at Measure phase and the Implementation phase would give them a clear picture of the improvement in the process performance. That's why a Z score is very necessary during the measure phase of DMAIC.