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Robust Computational Tools For Multiple Testing With Genetic Association Studies, William L. Welbourn Jr. May 2012

Robust Computational Tools For Multiple Testing With Genetic Association Studies, William L. Welbourn Jr.

All Graduate Theses and Dissertations

Resolving the interplay of the genetic components of a complex disease is a challenging endeavor. Over the past several years, genome-wide association studies (GWAS) have emerged as a popular approach at locating common genetic variation within the human genome associated with disease risk. Assessing genetic-phenotype associations upon hundreds of thousands of genetic markers using the GWAS approach, introduces the potentially high number of false positive signals and requires statistical correction for multiple hypothesis testing. Permutation tests are considered the gold standard for multiple testing correction in GWAS, because they simultaneously provide unbiased Type I error control and high power. However ...


Evaluating The Computational Efficiency Of Xfbat And Fbat For Family Based Studies, Yanwei Ouyang May 2006

Evaluating The Computational Efficiency Of Xfbat And Fbat For Family Based Studies, Yanwei Ouyang

All Graduate Plan B and other Reports

Family-based study designs are often employed when investigating the genetic causes of complex disease. While the transmission disequilibrium test (TDT) and its extensions were developed to use family data for assessing linkage between a known genetic marker and a disease-causing gene, the so-called FBAT approach proposed by Rabinowitz and Laird (2000) effectively subsumes these family-based procedures as special cases. FBAT is fully conditional, but its implementation in the freely available FBAT software package uses a large-sample distributional approximation to compute p-values. The exact distribution for FBAT can be enumerated, but doing so explicitly is computationally intensive, particularly for relatively larger ...


The Effect Of Item Format On Computation Subtest Scores Of Standardized Mathematics Achievement Tests, Larry Carcelli May 1981

The Effect Of Item Format On Computation Subtest Scores Of Standardized Mathematics Achievement Tests, Larry Carcelli

All Graduate Theses and Dissertations

The effect on childrens' scores of different item formats used in standardized mathematics achievement tests was investigated. Second grade students were given a mathematics computation test using formats derived from five standardized achievement tests. Identical content was tested with each format . Differences in test scores between types r0f formats were statistically significant at p(.001 (F = 45.25). These results indicate that what a student appears to know is substantially influenced by the format of the particualar test used in measuring achievement. These differences are not accounted for by the rno~mative scaling of the different tests. Greater attention should ...