Change-Point Analysis: A Powerful New Tool For Detecting Changes

WAYNE A. TAYLORBaxter Healthcare Corporation, Round Lake, IL 60073 Change-point analysis is a powerful new tool for determining whether a change has taken place. It is capable of detecting subtle changes missed by control charts. Further, it better characterizes the changes detected by providing confidence levels and confidence intervals. When collecting online data, a change-point […]

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A Pattern Test for Distinguishing Between Autoregressive and Mean-Shift Data

WAYNE A. TAYLORBaxter Healthcare Corporation, Round Lake, IL 60073 Statistical methods such as control charts and change-point analysis are commonly usedto determine whether the mean has shifted. Such methods assume independent errorsaround a possibly changing mean. When such techniques are applied to autoregressivedata, erroneous conclusions can result. However, shifts of the mean createautocorrelation between the

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Methods and Tools for Process Validation

Dr. Wayne A. Taylor ABSTRACT There are many statistical tools that can be used as part of validation. Control charts, capability studies, designed experiments, tolerance analysis, robust design methods, failure modes and effects analysis, sampling plans, and mistake proofing are but a few. Each of these tools will be summarized and their application in validation

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Selecting Statistically Valid Sampling Plans

INTRODUCTION Form 483 is used by the Food & Drug Administration (FDA) for reporting adverse findings resulting from one of their inspections.  Numerous 483’s have cited sampling plans as not being “statistically valid” or as lacking statistical justification.  So what does it take for a sampling plan to be statistically valid? Selecting statistically valid sampling

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Process Tolerancing: A Solution To The Dilemma Of Worst-Case Versus Statistical Tolerancing

Dr. Wayne A. Taylor When solving tolerancing problems, one must choose between worst-case tolerancing and statistical tolerancing.  Both of these methods have their pros and cons.  If worst-case tolerancing is used, all tolerances must be specified as worst-case tolerances. If statistical tolerancing is used, all tolerances must be specified as statistical tolerances.  In reality, the

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Alternative Sample Sizes for Verification Dose Experiments and Dose Audits

Dr. Wayne A. TaylorJoyce M. Hansen ABSTRACT ISO 11137 (1995), “Sterilization of Health Care Products – Requirements for Validation and Routine Control – Radiation Sterilization”, provides sampling plans for performing initial verification dose experiments and quarterly dose audits.  Alternative sampling plans are presented which provide equivalent protection.  These sampling plans can significantly reduce the cost

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Comparing Three Approaches To Robust Design: Taguchi Versus Dual Response Versus Tolerance Analysis

Presented at 1996 Fall Technical ConferenceDr. Wayne A. Taylor, Taylor Enterprises, Inc. (www.variation.com) Robustness is a key strategy for achieving high quality – low cost products and processes. Three different approaches to robust design are commonly used: the inner/outer array approach advocated by Taguchi, the dual response approach using response surfaces and the tolerance analysis

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