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Macau Periodical Index (澳門期刊論文索引)
- Author
- Cheng, W; Thaga, Keoagile
- Title
- Control charts for high yield processes
- Journal Name
- 澳門科技大學學報
- Pub. Info
- Jun. 2008, Vol.2, No.1, pp. 92-97
- Keyword
- High yield process；Binomial distribution；Poisson distribution；np chart；Q chart；Average run length
- Abstract
- Abstract : It has been suggested that the control chart based on normalized variables performs better than the usual control chart based on charting binomial random variables when the proportion of product nonconforming is small. We show in this paper that the Poisson approximation to binomial distribution is a better transformation since the binomial distribution is highly asymmetric when the fraction nonconforming is very small. In particular, using the Poisson approximation is equivalent to using the exact binomial distribution to monitor the process. Paragraph Headings: 1. Introduction 2. Binomial approximations 3. Control charts for a binomial process 4. Comparison of charts 5. Example 6. Conclusion Tables: 1. The probability functions for the three distributions with n = 1,000 and p = 0.001 2. The probability functions for the three distributions with n = 5,000 and p = 0.0003 3. The probability functions for the three distributions with n = 10,000 and p = 0.0007 4. The probability functions for the three distributions with n = 20,000 and p =0.00005 5. The false alarm probabilities 6. Comparison of the in-control ARL for three procedures Figures: 1. The np chart 2. The Poisson chart 3. The Q chart