Comments on zacks' recent paper on one-sided cusum procedures |
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Authors: | Volker Abel Rudolf Avenhaus |
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Affiliation: | University of the Federal Armed Forces Munich , D-8014 Neubiberq, Federal Republic of Germany |
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Abstract: | The goal of this paper is to propose approximations for the cdf and the inverse cdf of the normal sample median. The presented methodology, which seems to not have been investigated before, suggests to fit the normal sample median distribution with a symmetrical Johnson SU: distribution having ap-proximatively the same second and fourth moments. The results obtained with this approach, compared with the normal approximation, are very impressive, especially for the inverse cdf. One important application of the inverse cdf approximation of the normal sample median is the computation of accurate α‐level median/range control limits for any value of α (and not only for the popular value α = 0.0027). This paper can be also viewed as an homage to Professor N.L. Johnson's works by making a link between two of his major papers. |
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Keywords: | normal sample median distribution approximation of moments of order statistics Johnson's system of distributions |
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