Sökning: "variance estimator"

Visar resultat 1 - 5 av 70 avhandlingar innehållade orden variance estimator.

  1. 1. Calibration Adjustment for Nonresponse in Sample Surveys

    Författare :Bernardo João Rota; Thomas Laitila; Sune Karlsson; Risto Lehtonen; Örebro universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Auxiliary variables; Calibration; Nonresponse; principal com-ponents; regression estimator; response probability; survey sampling; two-step estimator; variance estimator; weighting; Statistics; Statistik;

    Sammanfattning : In this thesis, we discuss calibration estimation in the presence of nonresponse with a focus on the linear calibration estimator and the propensity calibration estimator, along with the use of different levels of auxiliary information, that is, sample and population levels. This is a fourpapers- based thesis, two of which discuss estimation in two steps. LÄS MER

  3. 2. On variance estimation for the two-phase regression estimator

    Författare :Martin Axelson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Informatics; computer and systems science; Informatik; data- och systemvetenskap; Informatics; computer and systems science; Informatik; data- och systemvetenskap; statistik; Statistics;

    Sammanfattning : Regression estimation under two-phase sampling is a cost-effective technique for estimating a finite population total. This dissertation consists of four papers, summarized in an introductory chapter, all of which focus on the use of auxiliary information in estimating the variance of the generalted regression estimator under two-phase sampling. LÄS MER

  4. 3. Uncertainty quantification for time varying quantities in turbulent flows

    Författare :Donnatella Xavier; Philipp Schlatter; Saleh Rezaeiravesh; Ricardo Vinuesa; David Moxey; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; uncertainty; variance estimator; autoregressive models; turbulence; computational fluid dynamics; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Quantification of uncertainty in results is crucial in both experiments and simulations of turbulence, yet this practice is notably underutilized. This thesis project delves into statistical tools within the framework of uncertainty quantification to systematically quantify uncertainties that occur in the time varying quantities of turbulence. LÄS MER

  5. 4. Aspects of analysis of small-sample right censored data using generalized Wilcoxon rank tests

    Författare :Marie-Louise Öhman; Hans Nyquist; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Censored generalized Wilcoxon rank test statistics; Variance estimation; Jackknifing; Influence function; Gross error sensitivity; Break-Down point; Sensitivity curve; Location parameter estimation; Product-Limit estimator and Monte-Carlo Simulation; Statistics; computer and systems science; Statistik; data- och systemvetenskap; Statistics; statistik;

    Sammanfattning : The estimated bias and variance of commonly applied and jackknife variance estimators and observed significance level and power of standardised generalized Wilcoxon linear rank sum test statistics and tests, respectively, of Gehan and Prentice are compared in a Monte Carlo simulation study. The variance estimators are the permutational-, the conditional permutational- and the jackknife variance estimators of the test statistic of Gehan, and the asymptotic- and the jackknife variance estimators of the test statistic of Prentice. LÄS MER

  7. 5. Estimating Interviewer Effects in Sample Surveys : Some Contributions

    Författare :Peter Lundquist; Stig Danielsson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Response variance; survey nonsampling error; interviewer effects; interpenetration; power; Statistics; Statistik;

    Sammanfattning : This thesis focuses on measurement errors that could be ascribed to the interviewers. To study interviewer variability a measurement error model is formulated which makes a clear distinction between three sources of randomness: the sample selection, interviewer assignment, and interviewing. LÄS MER