Effect of Deviation Based On Quality Parameter through Three Sigma

Statistical Quality Control (SQC) plays a significant role in the software testing for checking whether the software product satisfy the quality specifications or not. The foremost objective of this process is to find the defects or bugs in the software product. This results in the improvement in the quality of the software product and reduction in the maintenance cost. Bringing the software product under the quality control depends on the capability to analyze the performance of the product in a statistical way. A control chart is a Quality Control (QC) tool used to determine whether the software development process is in control state or not. The control charts aid to achieve and maintain the process stability by identifying the variations in the process. Generally, the six sigma and three-sigma are used as a quality measure in a manufacturing environment. This paper focuses on the three-sigma based on the effort metric in software testing. The Three-Sigma denotes the probability of process outcomes and the nature of prominent factors that affect the processes. It also looks for the causes such as known or unknown causes for the deviation from the average values. The three-sigma limits are used to set the upper and lower control limits in the SQC process. Under the normality condition, the Three-Sigma quality level yields 99.73% accuracy.