Sökning: "pattern-mixture models"

Hittade 2 avhandlingar innehållade orden pattern-mixture models.

1. 1. Attrition in Studies of Cognitive Aging

   Författare :Maria Josefsson; Xavier de Luna; Lars Nyberg; Anders Lundquist; Mattias Villani; Umeå universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Attrition; missing data; age-related cognitive change; non- ignorable dropout; monotone missing pattern; mixture models; pattern- mixture models; imputation; Statistics; statistik;

   Sammanfattning : Longitudinal studies of cognition are preferred to cross-sectional stud- ies, since they offer a direct assessment of age-related cognitive change (within-person change). Statistical methods for analyzing age-related change are widely available. LÄS MER

3. 2. Methods for longitudinal brain imaging studies with dropout

   Författare :Tetiana Gorbach; Xavier de Luna; Anders Lundquist; Martin A. Lindquist; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Missing data; nonignorable dropout; sensitivity analysis; uncertainty intervals; pattern-mixture models; aging; cognition; MRI; brain structure; resting-state functional connectivity; Statistics; statistik;

   Sammanfattning : One of the challenges in aging research is to understand the brain mechanisms that underlie cognitive development in older adults. Such aging processes are investigated in longitudinal studies, where the within-individual changes over time are observed. However, several methodological issues exist in longitudinal analyses. LÄS MER