This project will investigate theory, methods and applications of mathematical statistics and probability, with particular emphasis on the problems with data collected by NICHD. Current focus is on 1) the analysis of data arising from longitudinal studies with repeated measurements, 2)nonparametric procedures and the area under the receiver operating characteristic curve, 3) sample size for reference interval studies, 4) sequential clincial trials, and 5) general methodology for reproductive and perinatal epidemiology. Examples of NICHD projects on longitudinal studies are Successive Small-for-Gestational Age Study I and Study II in Alabama and Scandinavia, the Collaborative Perinatal Project and the Longitudinal Study of Vaginal Flora. A host of statistical procedures for estimation and hypothesis testing will be proposed and investigated for the time varying coefficient models via their asymptotic properties and simulations. Applications will be developed to handle questions concerning various issues in perinatal and reproductive epidemiology. Data will be fitted to growth models such as Rossavik model, linear model and logistic model. New and rigorous statistical methods and algorithms will be generated and validated through investigation of their statistical and probabilistic properties. Computer-intensive techniques such as bootstrapping methodology will be investigated for the relevant problems. Among the applications of the developed methodology are fetal growth, maternal risk factors and pregnancy outcomes. Statistical properties of some nonparametric procedures used for estimating the area under the receiver operating characteristic curve in the matched case-control samples are investigated. Various methodologies for the sample size calculation are developed for the reference interval studies. Another new direction is to develop sequential methodologies for clinical trials. Particular focus will be on the estimation problems following the termination of a clinical trial.
| Vexler, Albert; Wu, Chengqing; Yu, Kai Fun (2010) Optimal Hypothesis Testing: From Semi to Fully Bayes Factors. Metrika 71:125-138 |
| Wu, Mi-Xia; Yu, Kai-Fun; Liu, Ai-Yi (2009) Estimation of Variance Components in the Mixed-Effects Models: A Comparison Between Analysis of Variance and Spectral Decomposition. J Stat Plan Inference 139:3962-3973 |
| Zhang, Jun; Villar, Jose; Sun, Wenyu et al. (2007) Blood pressure dynamics during pregnancy and spontaneous preterm birth. Am J Obstet Gynecol 197:162.e1-6 |
| Levine, Richard J; Lam, Chun; Qian, Cong et al. (2006) Soluble endoglin and other circulating antiangiogenic factors in preeclampsia. N Engl J Med 355:992-1005 |
| Levine, Richard J; Qian, Cong; Maynard, Sharon E et al. (2006) Serum sFlt1 concentration during preeclampsia and mid trimester blood pressure in healthy nulliparous women. Am J Obstet Gynecol 194:1034-41 |
| Signore, Caroline; Mills, James L; Qian, Cong et al. (2006) Circulating angiogenic factors and placental abruption. Obstet Gynecol 108:338-44 |
| Troendle, James F; Liu, Aiyi; Wu, Chengqing et al. (2005) Sequential testing for efficacy in clinical trials with non-transient effects. Stat Med 24:3239-50 |
| Liu, Aiyi; Wu, Chengqing; Yu, Kai F et al. (2005) Supplementary analysis of probabilities at the termination of a group sequential phase II trial. Stat Med 24:1009-27 |
| Levine, Richard J; Qian, Cong; Leshane, Erik S et al. (2004) Two-stage elevation of cell-free fetal DNA in maternal sera before onset of preeclampsia. Am J Obstet Gynecol 190:707-13 |
| Klebanoff, Mark A; Schwebke, Jane R; Zhang, Jun et al. (2004) Vulvovaginal symptoms in women with bacterial vaginosis. Obstet Gynecol 104:267-72 |
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