Inconsistency in quality control is a major problem which plagues many indigenous firms in Nigeria. When product quality fluctuates, it negatively impacts on brand status, customer loyalty and confidence. The study was carried out to evaluate the best quality control practices for a brewing plant. Control charts were created and used for the analysis. These charts include the P-chart, C-chart, X-chart and R-chart. Product quality loss was determined to be 22. However, the X-chart was found to be the most suitable and effective. The values indicate that by using the X-chart model, about 96.4% of the suspected defective products would actually survive standard tests. This model has successfully eliminated the number of the proposed defective products to the barest minimum without altering the expected quality level of the final products.
Journal of the Nigerian Association of Mathematical Physics, Volume 19 (November, 2011), pp 405 – 412