4.3 Statistical Inference for a Single Sample The techniques of statistical inference can be classified into two broad categories: parame- ter estimation and hypothesis testing. We have already briefly introduced the general idea of point estimation of process parameters. hypothesis is a statement about the values of the parameters of a proba- bility distribution. For example, suppose we think that the mean in diameter of a bearing is 1.500 in. We may express this statement in a formal manner as