Sökning: "Sample selection"

Visar resultat 1 - 5 av 241 avhandlingar innehållade orden Sample selection.

  1. 1. Validering av urval

    Författare :Simon Wolming; Umeå universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES;

    Sammanfattning : This thesis consists of four papers, all of which are concerned with the validation of selection to higher education. In paper [I] student performance was observed for a period of three years with a sample of three different admission groups. LÄS MER

  3. 2. Essays on Sample Surveys : Design and Estimation

    Författare :Edgar Bueno; Per Gösta Andersson; Maria Giovanna Ranalli; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; GREG estimator; mixture distribution; probability proportional to size sampling; sampling algorithms; sampling design; sampling strategy; survey sampling; stratified sampling; Statistics; statistik;

    Sammanfattning : Sampling is a core stage in every survey. A sampling design carefully elaborated may imply not only a more accurate estimation of the parameters of interest, but also a reduction in the required sample size in a study. In this thesis we consider two particular but connected subjects. LÄS MER

  4. 3. Selection and ranking procedures based on likelihood ratios

    Författare :Jayanti Chotai; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Subset selection; likelihood ratio; hypothesis testing; order restrictions; normal distribution; uniform distribution; complete ranking; P* -condition; loss function;

    Sammanfattning : This thesis deals with random-size subset selection and ranking procedures• • • )|(derived through likelihood ratios, mainly in terms of the P -approach.Let IT , . .. LÄS MER

  5. 4. Covariate selection and propensity score specification in causal inference

    Författare :Ingeborg Waernbaum; Xavier de Luna; Elena Stanghellini; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Covariate selection; graphical models; matching; observational studies; treatment effects; unconfoundedness; Statistics; Statistik;

    Sammanfattning : This thesis makes contributions to the statistical research field of causal inference in observational studies. The results obtained are directly applicable in many scientific fields where effects of treatments are investigated and yet controlled experiments are difficult or impossible to implement. LÄS MER

  7. 5. Disentangling small genetic differences in large Atlantic herring populations: comparing genetic markers and statistical power

    Författare :Lena C. Larsson; Linda Laikre; Nils Ryman; Lorenz Hauser; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; conservation genetics; marine fish; spatial and temporal genetic variation; molecular marker comparison; allozyme; microsatellite; selection; fisheries management; Biology; Biologi; populationsgenetik; Population Genetics;

    Sammanfattning : Genes are the foundation of evolution and biodiversity. The genetic structure of natural populations needs to be understood to maintain exploited resources rationally. This thesis focuses on genetic variability and methods to determine spatial and temporal genetic heterogeneities. LÄS MER