Sökning: "Covariate selection"

Visar resultat 6 - 10 av 10 avhandlingar innehållade orden Covariate selection.

  1. 6. Extensions of the kernel method of test score equating

    Författare :Gabriel Wallin; Marie Wiberg; Jenny Häggström; Anton A. Béguin; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Test equating; Nonequivalent groups; Standard error of equating; bandwidth selection; log-linear models; item response theory; Statistics; statistik;

    Sammanfattning : This thesis makes contributions within the area of test score equating and specifically kernel equating. The first paper of this thesis studies the estimation of the test score distributions needed in kernel equating. LÄS MER

  3. 7. Methodological Studies on Covariate Model Building in Population Pharmacokinetic-Pharmacodynamic Analysis

    Författare :Ulrika Wählby; Thomas Ludden; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Pharmaceutical biosciences; Farmaceutisk biovetenskap; Biopharmacy; Biofarmaci; farmakokinetik och läkemedelsterapi; Pharmacokinetics and Drug Therapy;

    Sammanfattning : Population pharmacokinetic (PK) – pharmacodynamic (PD) modelling, using nonlinear mixed effects models, is increasingly being applied to obtain PK-PD information in drug development. Covariate modelling, the establishment of relationships between model parameters and patient characteristics, is undertaken to explain PK-PD variability and facilitate dose adjustment decisions, and is consequently an important objective of population PK-PD. LÄS MER

  4. 8. Development, Application and Evaluation of Statistical Tools in Pharmacometric Data Analysis

    Författare :Lars Lindbom; Niclas Jonsson; Mats Karlsson; Pascal Girard; Uppsala universitet; []
    Nyckelord :Pharmaceutical biosciences; pharmacometrics; pharmacokinetics; pharmacodynamics; methodology; statistics; model evaluation; resampling methods; Farmaceutisk biovetenskap;

    Sammanfattning : Pharmacometrics uses models based on pharmacology, physiology and disease for quantitative analysis of interactions between drugs and patients. The availability of software implementing modern statistical methods is important for efficient model building and evaluation throughout pharmacometric data analyses. LÄS MER

  5. 9. Estimation of hazard ratios from observational data with applications related to stroke

    Författare :Guilherme Barros; Jenny Häggström; Marie Eriksson; Daniel Nevo; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; survival analysis; causal inference; hazard ratios; marginal hazard ratio; stroke; balancing; Statistics; statistik;

    Sammanfattning : The objective of this thesis is to examine some challenges that may emerge when conducting time-to-event studies based on observational data. Time-to-event (also called survival) is a setting that involves analyzing how different factors may influence the length of time until an individual experiences the event of interest. LÄS MER

  7. 10. Generalized survival models as a tool for medical research

    Författare :Xingrong Liu; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : In medical research, many studies with the time-to-event outcomes investigate the effect of an exposure (or treatment) on patients’ survival. For the analysis of time-to-event or survival data, model-based approaches have been commonly applied. LÄS MER