Sökning: "covariates"

Visar resultat 1 - 5 av 89 avhandlingar innehållade ordet covariates.

  1. 1. Observed score equating with covariates

    Detta är en avhandling från Umeå : Department of Statistics, Umeå university

    Författare :Kenny Bränberg; Umeå universitet.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Equating; observed score equating; true scores; item response theory; linear equating function; equipercentile equating; kernel equating; covariates; linear regression; mean squared error; SOCIAL SCIENCES Statistics; computer and systems science Statistics; SAMHÄLLSVETENSKAP Statistik; data- och systemvetenskap Statistik; Statistics; statistik;

    Sammanfattning : In test score equating the focus is on the problem of finding the relationship between the scales of different test forms. This can be done only if data are collected in such a way that the effect of differences in ability between groups taking different test forms can be separated from the effect of differences in test form difficulty. LÄS MER

  2. 2. Structural Models of Network Contacts Between Actors Governed by Activity and Attraction

    Detta är en avhandling från Umeå : Department of Statistics, Umeå university

    Författare :Zhi Geng; Lunds universitet.; Lund University.; [2013]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Directed graph; Ego-nets; EM algorithm; Gibbs sampling; Multinomial distribution; Hypergeometric distribution; Vertex covariates; Clustering coefficient; Taylor expansion;

    Sammanfattning : This thesis consists of five papers on the subject of statistical modeling of stochastic networks. The NG-model proposed in Paper I combines a block structure with parameters that capture the identities of vertices and thus the new approach stresses the concept of ego-nets, which describes the structure around identified vertices. LÄS MER

  3. 3. Methodology for Handling Missing Data in Nonlinear Mixed Effects Modelling

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Åsa M. Johansson; Uppsala universitet.; [2014]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Pharmacometrics; population models; censored observations; missing covariates; missing dependent variable; missing data mechanism; missing completely at random MCAR ; missing at random MAR ; missing not at random MNAR ; estimation algorithms; Pharmaceutical Science; Farmaceutisk vetenskap;

    Sammanfattning : To obtain a better understanding of the pharmacokinetic and/or pharmacodynamic characteristics of an investigated treatment, clinical data is often analysed with nonlinear mixed effects modelling. The developed models can be used to design future clinical trials or to guide individualised drug treatment. LÄS MER

  4. 4. Aggressive antisocial behavior- clinical, cognitive, and behavioral covariates of its persistence

    Detta är en avhandling från Department of Clinical Sciences, Lund University

    Författare :Märta Wallinius; Lunds universitet.; Lund University.; Lunds universitet.; Lund University.; [2012]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; risk assessment; risk factors; externalizing spectrum; mental disorders; persistent criminality; violence; antisocial behavior; prevention;

    Sammanfattning : Popular Abstract in Swedish Introduktion Aggressivt antisocialt beteende utgör en stor utmaning för dagens samhälle, och undersökningar av vad som ligger bakom ett återkommande sådant beteende behövs för utvecklingen av våldspreventiva insatser. Syften & Metod Syftet med avhandlingen var att identifiera faktorer som samvarierar med återkommande aggressivt antisocialt beteende. LÄS MER

  5. 5. Multiple Time Scales and Longitudinal Measurements in Event History Analysis

    Detta är en avhandling från Umeå : Statistik

    Författare :Danardono; Umeå universitet.; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Statistics; Cox regression; multiple events; proportiona hazards; random effects; survival analysis; time-dependent covariates; time origin; Statistik; SOCIAL SCIENCES Statistics; computer and systems science Statistics; SAMHÄLLSVETENSKAP Statistik; data- och systemvetenskap Statistik; Statistics; statistik;

    Sammanfattning : A general time-to-event data analysis known as event history analysis is considered. The focus is on the analysis of time-to-event data using Cox's regression model when the time to the event may be measured from different origins giving several observable time scales and when longitudinal measurements are involved. LÄS MER