Pius Nderitu Kihara 2021. Model Calibration at Different Stages in Cluster Sampling; Use of Penalized Splines in Semiparametric Estimation. Recent Advances in Mathematical Research and Computer Science Vol. 4. (Nov. 2021), 1–14. DOI:https://doi.org/10.9734/bpi/ramrcs/v4/14456D.