Vol. 5 No. 3 (2015): Vol 5, Iss 3, Year 2015
Articles

Univariate statistical process control of super saver beans: a case of RMV supermarket, zimbabwe.

Romeo Mawonik
Great Zimbabwe University, P.O Box 1235 Masvingo, Zimbabwe
Vinscent Nkomo
Great Zimbabwe University, P.O Box 1235 Masvingo, Zimbabwe
Published June 30, 2015
Keywords
  • Statistical Process Control; Control charts; Autocorrelation; Time Series; CUSUM; EWMA.
How to Cite
Mawonik, R., & Nkomo, V. (2015). Univariate statistical process control of super saver beans: a case of RMV supermarket, zimbabwe. Journal of Management and Science, 5(3), 238-248. https://doi.org/10.26524/jms.2015.20

Abstract

Statistical Process Control (SPC) uses statistical techniques to improve the quality of a process reducing its variability. The main tools of SPC are the control charts. The basic idea of control charts is to test the hypothesis that there are only common causes of variability versus the alternative that there are special causes. Control charts are designed and evaluated under the assumption that the observations from the process are independent and identically distributed (IID) normal. However, the independence assumption is often violated in practice. Autocorrelation may be present in many procedures, and may have a significant effect on the properties of the control charts.Thus, traditional SPC charts are inappropriate for monitoring process quality. In this study, we
present methods for process control that deal with auto correlated data and a method based on time series ARIMA models (Box Jenkins Methodology). We apply the typical Cumulative Sum (CUSUM) and Exponentially Weighted Moving Average (EWMA) charts as SPC techniques and the time-series method in determining packaging process quality.

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