Sökning: "Variance components"
Visar resultat 1 - 5 av 93 avhandlingar innehållade orden Variance components.
1. Latent variable models for longitudinal twin data
Sammanfattning : Longitudinal twin data provide important information for exploring sources of variation in human traits. In statistical models for twin data, unobserved genetic and environmental factors influencing the trait are represented by latent variables. In this way, trait variation can be decomposed into genetic and environmental components. LÄS MER
2. Efficient strategies for collecting posture data using observation and direct measurement
Sammanfattning : Relationships between occupational physical exposures and risks of contracting musculoskeletal disorders are still not well understood; exposure-response relationships are scarce in the musculoskeletal epidemiology literature, and many epidemiological studies, including intervention studies, fail to reach conclusive results. Insufficient exposure assessment has been pointed out as a possible explanation for this deficiency. LÄS MER
3. Statistical Properties of Preliminary Test Estimators
Sammanfattning : This thesis investigates the statistical properties of preliminary test estimators of linear models with normally distributed errors. Specifically, we derive exact expressions for the mean, variance and quadratic risk (i.e. the Mean Square Error) of estimators whose form are determined by the outcome of a statistical test. LÄS MER
4. Numerical Algorithms for Optimization Problems in Genetical Analysis
Sammanfattning : The focus of this thesis is on numerical algorithms for efficient solution of QTL analysis problem in genetics.Firstly, we consider QTL mapping problems where a standard least-squares model is used for computing the model fit. LÄS MER
5. Understanding therapeutic traditions in a multilevel framework - new methodological approaches
Sammanfattning : Background: The observation of differences in the way apparently similar patients are treated from one health care setting to another, i.e., practice variation, have been recognized in numerous studies. The variations across the health care settings have been shown to exist for different outcomes. LÄS MER