UNP Journal of Statistics and Data Science
Vol. 3 No. 2 (2025): UNP Journal of Statistics and Data Science

An Application X-bar Chart and Statistical Process Control With R Package

Rizkiah, Niswatul (Unknown)
Yenni Kurniawati (Unknown)



Article Info

Publish Date
31 May 2025

Abstract

Quality control is a critical aspect of ensuring that production processes meet established standards and customer requirements. One widely used approach in Statistical Quality Control (SQC) is the control chart, particularly the X̄ and s charts, which monitor process stability based on the mean and variability of the data. This study aims to evaluate the quality and variation of the feed water boiler process using X̄ and s control charts, as well as to assess process capability with the aid of the R programming language and the qcc package. The dataset comprises hardness measurements of water collected over 25 consecutive days, three times per day, resulting in 75 observations. Initial analysis revealed one data point outside the control limit in the X̄ chart, which, when excluded, improved overall process stability. The s chart indicated more consistent stability compared to the X̄ chart. Process capability analysis yielded Cp and Cpk values of 0.5844 and 0.5600, respectively, indicating that the process is not yet capable of fully meeting product specifications and exhibits relatively high variability.These findings highlight the need for process improvement through variation reduction and six sigma approaches.The use of R/qcc proved to be an effective tool for monitoring and analyzing quality control in production processes.

Copyrights © 2025






Journal Info

Abbrev

ujsds

Publisher

Subject

Computer Science & IT Decision Sciences, Operations Research & Management Mathematics Social Sciences

Description

UNP Journal of Statistics and Data Science is an open access journal (e-journal) launched in 2022 by Department of Statistics, Faculty of Science and Mathematics, Universitas Negeri Padang. UJSDS publishes scientific articles on various aspects related to Statistics, Data Science, and its ...