Generalized class of estimators for finite population mean when study   variable is qualitative in nature
  This paper suggests a generalized class of estimators for population mean of the qualitative study variable in simple random sampling using information on an auxiliary variable. Asymptotic expressions of bias and mean square error of the proposed class of estimators have been obtained. Asymptotic optimum estimator has been investigated along with its approximate mean square error. It has been shown that proposed generalized class of estimators are more efficient than all the estimators considered by Singh et al. (2010) in case of qualitative study variable. In addition theoretical findings are supported by an empirical study based on real population to show the superiority of the constructed estimators over others. 
Prayas Sharma, Hemant K.Verma and Rajesh Singh
math.ST stat.TH