Search for dissertations about: "Covariates"

Showing result 1 - 5 of 123 swedish dissertations containing the word Covariates.

  1. 1. Observed score equating with covariates

    Author : Kenny Bränberg; Marie Wiberg; Xavier de Luna; Dag Sörbom; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; 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; Statistics; Statistik; Statistics; statistik;

    Abstract : 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. READ MORE

  2. 2. Prediction Methods for High Dimensional Data with Censored Covariates

    Author : Caroline Svahn; Oleg Sysoev; Mattias Villani; Fredrik Gunnarsson; Xavier de Luna; Linköpings universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; statistics; machine learning; censored covariates; statistik; maskininlärning; censurerade kovariater;

    Abstract : While access to data steadily increases, not all data are straight-forward to use for prediction. Censored data are common in several industrial scenarios, and typically arise when there are some limitations to measuring equipment such as for instance concentration measuring equipment in chemistry or signal receivers in signal processing. READ MORE

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

    Author : Zhi Geng; Statistiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Directed graph; Ego-nets; EM algorithm; Gibbs sampling; Multinomial distribution; Hypergeometric distribution; Vertex covariates; Clustering coefficient; Taylor expansion;

    Abstract : 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. READ MORE

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

    Author : Åsa M. Johansson; Mats O. Karlsson; Andrew C. Hooker; Leon Aarons; Uppsala universitet; []
    Keywords : MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; 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;

    Abstract : 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. READ MORE

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

    Author : Märta Wallinius; Malmö Rättspsykiatri; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; risk assessment; risk factors; externalizing spectrum; mental disorders; persistent criminality; violence; antisocial behavior; prevention;

    Abstract : Introduction Aggressive antisocial behavior is a major challenge to society, and studies on the determinants of its persistence are essential to the development of strategies to prevent violence. Aims & Methods The overall aim of the thesis was to establish covariates of persistent aggressive antisocial behavior in a population-based cohort and in clinically evaluated, prospectively followed, offender groups. READ MORE