VOLUME - 6, ISSUE – 2 , JULY.TO DEC ,2020 ISSN NO. : 2455-4642 (ONLINE)
IDEES –International Multidisciplinary Research Journal
(Peer Reviewed)
A Research Paper
on
Performance of Regression chart under Three Delta Control Limits and
Six Delta Initiatives
By
Kalpesh S. Tailor
Assistant Professor,
Department of Statistics, M.K. Bhavnagar University, Bhavnagar-364001
Abstract:
A control chart is a graphical device for representation of the data for knowing the extent of
variations from the expected standard. The technique of control chart was suggested by W.A.
Shewhart of Bell Telephone Company based on three sigma limits. M. Harry, the engineer of
Motorola has introduced the concept of six sigma in 1980. In six sigma initiatives, it is
expected to produce 3.4 or less number of defects per million of opportunities. Moderate
distribution proposed by Naik V.D and Desai J.M, is a sound alternative of normal
distribution, which has mean and mean deviation as pivotal parameters and which has
properties similar to normal distribution. Naik V.D and Tailor K.S. have suggested the
concept of 3-delta control limits and developed various control charts based on this
distribution. In this paper an attempt is made to construct a control chart based on three delta
and six delta initiatives for regression. Suitable Table for mean deviation is also constructed
and presented for the engineers for making quick decisions.
Key words: Moderate distribution, X-bar, Standard deviation, Six Delta.
1. Introduction:
The conventional quality control charts developed by W. A. Shewhart (1931) were based on
normality assumptions and control limits are calculated using 3sigma distance from the
expected level of quality. The concept of six-sigma was introduced by Motorola by the
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