Διαγράμματα ελέγχου διαμέσου
Median control charts
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Keywords
Διαγράμματα ελέχου ; Διάμεσος ; Στατιστικός έλεγχος διεργασιών ; Στατιστικός έλεγχος ποιότηταςAbstract
Shewhart control charts are a significant and powerful tool in an attempt towards a more
stable production process. Through these charts, possible deviations on various product
parameters can be controlled, which if not identified in time, could possibly lead to an out
of control process. Effective use of Shewhart control charts results in the production of
optimum quality products and minimize the production of non-conforming ones. Usually,
two types of control charts for variables are compiled. One chart for monitoring the
process mean and one for monitoring the process variability.
The median 𝑋 chart is a popular chart for monitoring the mean of a process. Although
the mean chart 𝑋 is a more efficient chart, the median chart is a useful alternative, with
an interesting performance. The main advantages of the median chart are that it is
simpler than the 𝑋 chart and it is robust against outliers or small deviations from
normality.
The present thesis is divided into four chapters. The first chapter describes the
control charts for monitoring the mean value and variability of a process. In addition, the
average run length is presented as well as mean and variability estimators used in the
control charts. In the second chapter, Shewhart-type median control charts are studied
in detail, for both Phase II and Phase I. Their performance is evaluated through the
average run length for various sample sizes and different shifts in the process mean. In
the third chapter, CUSUM-type median control charts are examined analytically, while in
Chapter 4 the EWMA-type median control charts are studied in detail. Their performance
is evaluated through the average run length and results are presented for various
combinations of their parameters and different shifts in the process mean.
Postgraduate Studies Programme
Εφαρμοσμένη ΣτατιστικήDepartment
Σχολή Χρηματοοικονομικής και Στατιστικής. Τμήμα Στατιστικής και Ασφαλιστικής ΕπιστήμηςNumber of pages
122Language
GreekCollections
Except where otherwise noted, this item's license is described as
Αναφορά Δημιουργού 3.0 Ελλάδα
Αναφορά Δημιουργού 3.0 Ελλάδα