The paper contributes deriving the confidence intervals according to the use types of hypothesis tests. The guidelines of usuage on the types of hypothesis tests and interval estimation are proposed. These formulars can be used to evaluate the effects of quality improvement activity.

The present study proposes the various hypothesis tests and interval estimations for homogeneous and heterogeneous populations in the continuous and discrete process. These results can be used to complement the QC story 15 steps for quality improvement circle and DMAIC processes for six sigma innovation.