https://staging.ncbae.edu.pk/k_course/multivariate-ratio-and-exponential-estimators-for-population-variance-in-two-phase-sampling-using-multi-auxiliary-variables-amber-asghar/ National College of Business administration & Economics Mon, 26 Mar 2018 08:02:09 +0000 hourly 1 https://wordpress.org/?v=6.9.1