For the design and improvement of a product or process. Taguchi proposed an experimental method in which the so called orthogonal array is used as an experimental design. However, it is not clear how his orthogonal arrays are constructed and what statistical properties they possess. In this thesis, it is shown that the Taguchi orthogonal arrays can be constructed using the traditional orthogonal main effect plans. Besides, a systematic procedure is developed for allocating factors to an orthogonal array without using the cumbersome linear graph or interaction graph. Finally, a method is presented to determine alias relations in some Plackett-Burman designs and other asymmetrical orthogonal arrays.
