Modelling variation in industrial experiments

For off-line quality control, the Taguchi method now receives much attention in industry. It effectively combines engineering knowledge with the power of the design of experiments, to minimize variability at the design stage of products and processes and to set the process level at the target value. The paper discusses the analysis of Taguchi experiments and proposes a simple and flexible model for the mean and variation of the data, as well as a model parameter estimation method that is based on sound statistical principles. Data from an industrial experiment are included for illustration.