Sökning: "missing covariates"
Visar resultat 1 - 5 av 6 avhandlingar innehållade orden missing covariates.
1. Methodology for Handling Missing Data in Nonlinear Mixed Effects Modelling
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
2. Uncertainty intervals and sensitivity analysis for missing data
Sammanfattning : In this thesis we develop methods for dealing with missing data in a univariate response variable when estimating regression parameters. Missing outcome data is a problem in a number of applications, one of which is follow-up studies. LÄS MER
3. Interpretable machine learning models for predicting with missing values
Sammanfattning : Machine learning models are often used in situations where model inputs are missing either during training or at the time of prediction. If missing values are not handled appropriately, they can lead to increased bias or to models that are not applicable in practice without imputing the values of the unobserved variables. LÄS MER
4. Valid causal inference in high-dimensional and complex settings
Sammanfattning : The objective of this thesis is to consider some challenges that arise when conducting causal inference based on observational data. High dimensionality can occur when it is necessary to adjust for many covariates, and flexible models must be used to meet convergence assumptions. The latter may require the use of a novel machine learning estimator. LÄS MER
5. Mathematical programming for optimal probability weighting
Sammanfattning : In spite of the fact that probability weighting is widely used in statistics to correct for unequal sampling, control for confounding, and handle missing data, it has two main limitations. First, statistical inferences may be inefficient in the presence of extreme probability weights. LÄS MER