Loading...
Improved Wald Transformation p-Chart For Nonconforming Fraction
Author(s)
Sinsomboonthong, Juthaphorn
Date Issued
January 1, 2025
Type
Article
Abstract
This study proposes a new improved transformation p-chart for nonconforming fraction of a production process, called improved Wald transformation p-chart. Via a simulation study, the efficiency of the proposed control chart was compared with the traditional p-chart, the improved square root transformation p-chart, and the Wilson p-chart. The simulation was conducted using the Monte Carlo technique for 180 situations and 10,000 times for each situation. The studied situations were as follows: the nonconforming fraction was set to be 0.01, 0.02, 0.05, 0.07, and 0.09; the shift of the nonconforming fraction was set to be 1.1, 1.3, 1.5, 2.0, 3.0, and 4.0; and the sample size (n) was set to be 30, 50, 100, 300, 500, and 1000 . The efficiency measures were out-of-control average run length and standard deviation of the run length. The results showed that the proposed chart was the most efficient among the four tested charts for a large sample size. In addition, the proposed chart tended to perform with the best efficiency for large sample sizes, n ≥ 500, and small nonconforming fraction below 0.1. It performed well with all the tested shifts of nonconforming fraction. However, the sensitivity to detect out-of-control items in the production process seemed to be same among the tested charts for smaller sample size, n < 500.
Citation
Journal of Applied Science and Engineering, 28(4), 767-781, 2025