Journal of Applied Science and Engineering

Published by Tamkang University Press


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Smiley W. Cheng This email address is being protected from spambots. You need JavaScript enabled to view it.1 and Hansheng Xie1

1Department of Statistics, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2


Received: March 1, 2000
Accepted: September 1, 2000
Publication Date: September 1, 2000

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In dealing with positively-skewed distributed data, the direct logarithmic transformation may result in a control chart with inappropriate control parameters in the application of quality control. When a specific interval for the lognormal mean is given, a new method is introduced to set up two control charts and these two charts can monitor a process for which the underlying distribution of the quality characteristic is lognormal.

Keywords: lognormal distribution, control chart, quality control, mean, variance, normal distribution


  1. [1] Ferrell, E. D., “Control Charts for Lognormal Universe,” Industrial Quality Control, V. 15, pp. 4-6 (1958).
  2. [2] Morrison, J. , “The Lognormal Distribution in Quality Control,” Applied Statistics, V. 7, pp. 160-172 (1958).
  3. [3] Xie, H., Contributions to Qualimetry. Ph.D. dissertation, University of Manitoba, Winnipeg, Canada, (1999).