Fuzzy confidence interval construction and its application in recovery time for COVID-19 patients

An approach is proposed to construct fuzzy confidence intervals for unknown parameters in statistical models. In this approach, a family of confidence intervals of the unknown crisp parameter has been considered. Such confidence intervals are used to obtain a fuzzy confidence interval for the parameter of interest. ‎The proposed approach benefits a wide range of confidence intervals to obtain a trapezoidal shaped fuzzy set of the parameter space as the fuzzy confidence interval for the parameter of interest. By using the resolution identity, it is shown that the constructed fuzzy confidence intervals are really fuzzy sets of the parameter space.Some numerical examples are provided to explain the approach in one-sided and two-sided fuzzy confidence intervals. ‎‎Moreover, ‎an‎‎‎ application in health sciences ‎‎‎is provided about the ‎‎‎‎recovery time of olfactory and gustatory dysfunctions for COVID-19 patients.