2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/218243In this paper exponential ratio and exponential product type estimators using two auxiliary variables are proposed for estimating unknown population variance $S_y^2$. Problem is extended to the case of two-phase sampling. Theoretical results are supported by an empirical study.8 pagesGeneral Mathematics65C60text