Approximate confidence interval for generalized Taguchi process capability index

The impreciseness happens in the quality control same as other statistical problems. In quality control where specification limits are better expressed by fuzzy sets, the generalized process capability indices C_p~, C_pk~ and C_pm~ can be helpful and necessary for measuring the capability. We propose a generalized form of Taguchi index C_pm~ to assess the ability of the fuzzy process to be clustered around the target value. An approximate 100(1-γ)% confidence interval for the generalized process capability index C_pm~ by using fuzzy specification limits is also presented.