  Singh and Kumar (2011) suggested estimators for calculating population
variance using auxiliary attributes. This paper proposes a family of estimators
based on an adaptation of the estimators presented by Kadilar and Cingi (2004)
and Singh et al. (2007), and introduces a new family of estimators using
auxiliary attributes. The expressions of the mean square errors (MSEs) of the
adapted and proposed families are derived. It is shown that adapted estimators
and suggested estimators are more efficient than Singh and Kumar (2011)
estimators. The theoretical findings are supported by a numerical example.
