Transformation of the Independent Variables
Experimental work is concerned with the study of a response function N = E(y) = f(x, o) where x are the levels of k variables and o is a set of p parameters. The objective is usually to check the adequacy of the assumed functional form, to estimate the values of the parameters o and hence the response E(y) at any chosen x, and to obtain easures of precision for the estimates. In the present investigation, the errors in the y's are at least approximately normally and independently distributed with constant variance, and concentration is on finding transformations in the x's to reduce the function in these transformed variables to as simple a form as possible. Although not limited to this application, the method is perhaps of most general use when the true form f(x, o) of the response function is unknown. This is represented by a graduating function. (Author).