Graphic communication in detecting outlier cases in time column control diagram

Abstract

Abstract Control diagrams are graphical communication media that can be used as tools in the process of controlling statistics statistically to assist in monitoring and improving a quality process by helping to separate specific cause and general cause variables. Basically the control diagram plots the area of acceptance of a hypothesis test. This study aims to detect disruptive causes in the control diagram in time series cases and to justify the statistical model in accordance with the procedure. A process is said to be controlled if the observational data from that process behaves like random iid variables (independent identically distributed), and if it is not controlled, it is out of control. The study uses 25 days’ time series observational data in PT. Guccitex Cimahi. In this time frame analysis, research that is influenced by specific causes can be treated as outliers of the time series model and can be detected by outlier detection methods. The results in this study explain that a traditional control diagram is very dependent on the assumption of iid (independent identically distributed). Application in real life faces observations that are not iid (independent identically distributed), which show the effects of trends, seasonality, and other influences. The control diagram is in principle the same, using time series analysis to overcome these effects by plotting the area of acceptance of a hypothesis test, but if the process is not controlled, the control diagram cannot provide any guidance, so it is necessary to do a data analysis using analysis time series.