Sökning: "covariates"

Visar resultat 6 - 10 av 131 avhandlingar innehållade ordet covariates.

  1. 6. Multiple Time Scales and Longitudinal Measurements in Event History Analysis

    Författare :Danardono; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Statistics; Cox regression; multiple events; proportiona hazards; random effects; survival analysis; time-dependent covariates; time origin; Statistik; Statistics; 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

  3. 7. Bilingual education cognitive development and school achievement : a study of the bilingual programs for Tibetan children

    Författare :Yu Qiang; Katrin Goldstein Kyaga; Stockholms universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; bilingualism; bilingual education; cognitive development; threshold hypothesis; study variable; covariates the third variables ; path analysis; direct effects; total effects.; internationell pedagogik; International Education;

    Sammanfattning : This study examines the effects of two models of school bilingual programs on Tibetan children's cognitive development and school achievement.Based on the findings of empirical studies, Cummins' threshold theory was critically evaluated. LÄS MER

  4. 8. Reliability analysis and maintenance scheduling considering operating conditions

    Författare :Dhananjay Kumar; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mining and Rock Engineering; Gruv- och Berganläggningsteknik;

    Sammanfattning : In reliability analysis failure times are often considered as the only factor that can explain the reliability characteristics of a system. This may be insufficient. Operating conditions and other factors (e.g. LÄS MER

  5. 9. Covariate selection and propensity score specification in causal inference

    Författare :Ingeborg Waernbaum; Xavier de Luna; Elena Stanghellini; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Covariate selection; graphical models; matching; observational studies; treatment effects; unconfoundedness; Statistics; Statistik;

    Sammanfattning : This thesis makes contributions to the statistical research field of causal inference in observational studies. The results obtained are directly applicable in many scientific fields where effects of treatments are investigated and yet controlled experiments are difficult or impossible to implement. LÄS MER

  7. 10. Monotonic and Semiparametric Regression for the Detection of Trends in Environmental Quality Data

    Författare :Mohamed Hussian; Anders Grimvall; Ali Hadi; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Normalisation; Monotonic; Semiparametric; Temporal trends; fluctuations; global; local; Matematisk statistik; Icke-parametriska metoder; Statistics; Statistik;

    Sammanfattning : Natural fluctuations in the state of the environment can long conceal or distort important trends in the human impact on our ecosystems. Accordingly, there is increasing interest in statistical normalisation techniques that can clarify the anthropogenic effects by removing meteorologically driven fluctuations and other natural variation in time series of environmental quality data. LÄS MER