Year
2026
Season
Spring
Paper Type
Master's Thesis
College
College of Arts and Sciences
Degree Name
Master of Science in Mathematical Sciences (MS)
Department
Mathematics & Statistics
NACO controlled Corporate Body
University of North Florida. Department of Mathematics and Statistics
Committee Chairperson
Dr. Elena Buzaianu
Second Advisor
Dr. Ping Sa
Rights Statement
http://rightsstatements.org/vocab/InC/1.0/
Third Advisor
Dr. Fei Heng
Fourth Advisor
Dr. Peiyao Wang
Department Chair
Dr. Richard F. Patterson
College Dean
Dr. Kaveri Subrahmanyam
Abstract
Dunnett’s procedure is widely used for comparing multiple treatments with a control, but its application becomes challenging in the presence of missing data and multiple com- parisons. An improved Dunnett-type procedure addresses this by using multiple imputation under Rubin’s framework and constructing unified confidence intervals based on a multi- variate t distribution, allowing valid simultaneous inference while controlling the family-wise error rate (FWER). This work further extends the method by incorporating shrinkage-based variance estimation. Specifically, individual group variances are shrunk toward a common value to improve stability. This approach is particularly effective when group variances are similar or moderately different, as it reduces estimation variability, though it may intro- duce bias when variances differ substantially. Simulation results show that the proposed method maintains nominal joint coverage, preserves good precision as missingness increases, and achieves reliable FWER control. Overall, this approach provides a practical and robust extension of Dunnett-type inference for incomplete data.
Suggested Citation
Habibullah, Md, "Variance shrinkage in Dunnett-type multiple comparisons with missing data" (2026). UNF Graduate Theses and Dissertations. 1416.
https://digitalcommons.unf.edu/etd/1416
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