Nonresponse in sample surveys: new estimation and inference methods

In this manuscript, the topic of nonresponse in surveys is studied through several research projects. We address different subjects as treatment of nonresponse in data sets, estimation in presence of nonresponse and analysis of variance estimators. The first chapter of this thesis is devoted to an introduction to survey sampling and to the concepts used in the rest of this manuscript. In the second chapter, a new method for donor imputation of nonresponse is proposed. In the chapter 3, we present a new estimator of population total in the presence of nonresponse, which combines model-assisted estimators and estimators weighted by nonresponse. In a fourth chapter, we raise a problem related to variance estimators of total estimator when the ratio between the number of variables and the number of observations is large. We approximate the bias of the variance estimators in order to adjust the estimators. The chapter 5 of this manuscript deals with a different subject. We propose a new spatiotemporal sampling method that takes into account both sources of spatial and temporal autocorrelations. The method enables us to select a sample that is well spread in time and in space.