Process Capability Analysis Using MINITAB (II)

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Process Capability Analysis Using MINITAB (II) By Keith M. Bower, Abstract This paper builds on the content covered in the previous edition of EXTRAOrdinary Sense. Frequently, quality practitioners find that the assumption of modeling a Process Using the Normal distribution is not valid. This paper addresses two approaches to dealing with this type of scenario, and offers a decision making criterion for choosing between two techniques for a given set of data. Assumptions As was discussed in the earlier paper, there are two crucial assumptions to consider when performing Process Capability analyses, namely: 1. The Process is in statistical control. 2. The distribution of the Process considered is Normal. As is discussed by Walker1, Abraham De Moivre first discovered the Normal distribution in 1733.

Frequently, statisticians make use of the Weibull distribution for modeling purposes. The capability analysis in Figure 6 shows the corresponding analysis assuming a Weibull

  Analysis, Process, Capability, Weibull, Process capability analysis