A Multistate Competing Risks Framework For Preconception Prediction Of Pregnancy Outcomes,
2022
Harvard Pilgrim Health Care Institute
A Multistate Competing Risks Framework For Preconception Prediction Of Pregnancy Outcomes, Kaitlyn Cook, Neil J. Perkins, Enrique Schisterman, Sebastien Haneuse
Statistical and Data Sciences: Faculty Publications
Background: Preconception pregnancy risk profiles—characterizing the likelihood that a pregnancy attempt results in a full-term birth, preterm birth, clinical pregnancy loss, or failure to conceive—can provide critical information during the early stages of a pregnancy attempt, when obstetricians are best positioned to intervene to improve the chances of successful conception and full-term live birth. Yet the task of constructing and validating risk assessment tools for this earlier intervention window is complicated by several statistical features: the final outcome of the pregnancy attempt is multinomial in nature, and it summarizes the results of two intermediate stages, conception and gestation, whose outcomes …
Statistical Challenges And Methods For Missing And Imbalanced Data,
2022
Utah State University
Statistical Challenges And Methods For Missing And Imbalanced Data, Rose Adjei
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Missing data remains a prevalent issue in every area of research. The impact of missing data, if not carefully handled, can be detrimental to any statistical analysis. Some statistical challenges associated with missing data include, loss of information, reduced statistical power and non-generalizability of findings in a study. It is therefore crucial that researchers pay close and particular attention when dealing with missing data. This multi-paper dissertation provides insight into missing data across different fields of study and addresses some of the above mentioned challenges of missing data through simulation studies and application to real datasets. The first paper of …
Estimation Of The Parameters In A Mixture Of Two Normal Distributions And The Generalized Pivotal Quantity Method,
2022
University of Nevada, Las Vegas
Estimation Of The Parameters In A Mixture Of Two Normal Distributions And The Generalized Pivotal Quantity Method, Md Faruk Hossain
UNLV Theses, Dissertations, Professional Papers, and Capstones
A pivotal quantity is a random variable that is a function of both the random data and the unknown population parameters and whose probability distribution does not depend on any of the unknown parameters. The population parameters here may include nuisance parameters. Historically, pivotal quantities have been used for the construction of test statistics for hypothesis testing of some of these unknown parameters. They have also been used for the construction of confidence intervals for some of these parameters.Generalized pivotal quantities (GPQ) were introduced by Tsui and Weerahandi (1989) and Weerahandi (1993). A GPQ is a function, not only of …
Use Of Healthcare Utilization Records For Analyzing Trends In Clinical Toxoplasmosis: A Comparison Of Nevada And The United States,
2022
University of Nevada, Las Vegas
Use Of Healthcare Utilization Records For Analyzing Trends In Clinical Toxoplasmosis: A Comparison Of Nevada And The United States, Elijah Kreutzer
UNLV Theses, Dissertations, Professional Papers, and Capstones
Toxoplasmosis, a zoonotic disease caused by the parasitic protist Toxoplasma gondii, is a ubiquitous, global public health concern with a wide variety of clinical manifestations. Surveillance for the disease is lacking even in developed countries, and what surveillance is present most often focuses on pregnant women. This research investigated trends in clinical toxoplasmosis in Nevada and nationally to address the lack of knowledge concerning how Nevada discharges compare to national discharges in cases of toxoplasmosis. Specifically, this research sought to determine what characterizes toxoplasmosis in Nevada across inpatient, outpatient, and emergency department settings, as well as how these cases differ …
Bayesian Nonparametric Regression Models For Insurance Claims Frequency And Severity,
2022
University of Nevada, Las Vegas
Bayesian Nonparametric Regression Models For Insurance Claims Frequency And Severity, Mostafa Shams Esfand Abadi
UNLV Theses, Dissertations, Professional Papers, and Capstones
The prediction of future insurance claims frequency and severity is one of the most important problems in actuarial science. Such predictions help the actuary set insurance premiums based on observed risk factors, or covariates. Accuracy of these predictions is important from the point of view of both the insurance company as well as the insured customer. Typically, actuaries use parametric regression models to predict claims based on the covariate information. Such models assume the same functional form tying the response to the covariates for each data point. These models are not flexible enough and fail to accurately capture at the …
Retrospective Varying Coefficient Association Analysis Of Longitudinal Binary Traits,
2022
University of Nevada, Las Vegas
Retrospective Varying Coefficient Association Analysis Of Longitudinal Binary Traits, Gang Xu
UNLV Theses, Dissertations, Professional Papers, and Capstones
Many genetic studies contain rich information on longitudinal phenotypes that require powerful analytical tools for optimal analysis. Genetic analysis of longitudinal data that incorporates temporal variation is important for understanding the genetic architecture and biological variation of complex diseases. Most of the existing methods assume that the contribution of genetic variants is constant over time and fails to capture the dynamic pattern of disease progression. However, the relative influence of genetic variants on complex traits fluctuates over time.We developed several tests to fill the gap of analyzing time-varying genetic effects in longitudinal GWAS for binary traits. First, we propose a …
A Probabilistic Formalisation Of Contextual Bias: From Forensic Analysis To Systemic Bias In The Criminal Justice System,
2022
Swarthmore College
A Probabilistic Formalisation Of Contextual Bias: From Forensic Analysis To Systemic Bias In The Criminal Justice System, M. Cuellar, J. Mauro, Amanda Luby
Mathematics & Statistics Faculty Works
Researchers have found evidence of contextual bias in forensic science, but the discussion of contextual bias is currently qualitative. We formalise existing empirical research and show quantitatively how biases can be propagated throughout the legal system, all the way up to the final determination of guilt in a criminal trial. We provide a probabilistic framework for describing how information is updated in a forensic analysis setting by using the ratio form of Bayes’ rule. We analyse results from empirical studies using this framework and employ simulations to demonstrate how bias can be compounded where experiments do not exist. We find …
(R1974) A Multi Server Markovian Working Vacation Queue With Server State Dependent Rates And With Partial Breakdown,
2022
CK College of Engineering and Technology
(R1974) A Multi Server Markovian Working Vacation Queue With Server State Dependent Rates And With Partial Breakdown, A. Sundaramoorthy, R. Kalyanaraman
Applications and Applied Mathematics: An International Journal (AAM)
In this article, we consider an M/M/C queue in which the arrival rate and service rate depends on the state of the system. In addition, the servers takes working vacation and the system may breakdown. Whenever breakdown takes place, the repair process immediately commences. During the repair period the customers are given service in a reduced service rate. Based on the vacation termination point, two models have been defined. The steady state probability vector of the number of customers in the queue and the stability condition are obtained using Matrix-Geometric method. The stationary waiting time distributions have been obtained. Some …
Weather Parameters Influencing The Incidence Of Citrus Canker Caused By Aw Strain In The Rio Grande Valley,
2022
The University of Texas Rio Grande Valley
Weather Parameters Influencing The Incidence Of Citrus Canker Caused By Aw Strain In The Rio Grande Valley, Amit Sharma
Theses and Dissertations
Citrus canker caused by bacterium Xanthomonas citri subsp. citri (Xcc) seriously affects the citrus industry by making the fruit unmarketable due to unsightly lesions on the fruit. Canker caused by Aw strain of Xcc was reported in the citrus trees located in the residential areas of the Rio Grande Valley (RGV). Canker severity differs amongst cultivars/varieties, and it is influenced by prevailing environmental conditions. Multiple regression modeling of the disease incidence with the environmental variables such as temperature, humidity, windspeed, wind gust, and rainfall was performed to understand the environmental conditions that are favorable for spread of citrus …
Estimating The Distribution Of Ratio Of Paired Event Times In Phase Ii Oncology Trials,
2022
University of Kentucky
Estimating The Distribution Of Ratio Of Paired Event Times In Phase Ii Oncology Trials, Li Chen, Mark Burkard, Jianrong Wu, Jill M. Kolesar, Chi Wang
Markey Cancer Center Faculty Publications
With the rapid development of new anti-cancer agents which are cytostatic, new endpoints are needed to better measure treatment efficacy in phase II trials. For this purpose, Von Hoff (1998) proposed the growth modulation index (GMI), that is, the ratio between times to progression or progression-free survival times in two successive treatment lines. An essential task in studies using GMI as an endpoint is to estimate the distribution of GMI. Traditional methods for survival data have been used for estimating the GMI distribution because censoring is common for GMI data. However, we point out that the independent censoring assumption required …
Bayesian Adaptive Clinical Trial Design,
2022
The Texas Medical Center Library
Bayesian Adaptive Clinical Trial Design, Mengyi Lu
Dissertations and Theses (Open Access)
The landscape of drug development in oncology has changed from conventional chemotherapies to molecular targeted therapies and immunotherapies, which provide innovative therapeutic modalities for treating cancers. These novel therapeutic agents work through mechanisms that fundamentally differ from standard chemotherapeutic agents, making the conventional trial design paradigm inefficient and dysfunctional. Specifically, the focus of dose-finding trials has shifted from finding the maximum tolerated dose (MTD) to the optimal biological dose (OBD), defined as the dose that optimizes the risk–benefit tradeoff. How to accurately identify the OBD and its dosing schedule is of great importance to maximize efficacy and safety of targeted …
Infrastructure Development For Personalized Risk Prediction To Reduce Cardiovascular Disease In Childhood Cancer Survivors,
2022
The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences
Infrastructure Development For Personalized Risk Prediction To Reduce Cardiovascular Disease In Childhood Cancer Survivors, Suman Shrestha
Dissertations and Theses (Open Access)
Although childhood cancer survivors have lengthy life expectancies, they run the risk of experiencing long-term health issues as a result of their treatment. The most frequent non-cancerous cause of morbidity and mortality for these survivors is cardiac disease. Radiation therapy (RT) has been linked in numerous cohort studies to a higher chance of developing a late cardiac disease in these survivors, and this risk rises with higher mean heart doses and increased RT exposure to larger cardiac volumes. Since, the heart is a heterogeneous organ made up of several distinct substructures, RT dose received by the entire heart does not …
Statistical Methods For Modern Threats,
2022
Clemson University
Statistical Methods For Modern Threats, Brandon Lumsden
All Dissertations
More than ever before, technology is evolving at a rapid pace across the broad spectrum of biological sciences. As data collection becomes more precise, efficient, and standardized, a demand for appropriate statistical modeling grows as well. Throughout this dissertation, we examine a variety of new age data arising from modern technology of the 21st century. We begin by employing a suite of existing statistical techniques to address research questions surrounding three medical conditions presenting in public health sciences. Here we describe the techniques used, including generalized linear models and longitudinal models, and we summarize the significant associations identified between research …
Estimation Of Disaggregated Import Demand Functions For Nigeria,
2022
Lagos Businss School, Pan Atlantic University, Lagos.
Estimation Of Disaggregated Import Demand Functions For Nigeria, Chekwube V. Madichie, Uche C. Nwogwugwu, Franklin N. Ngwu, Olisaemeka D. Mauka
CBN Journal of Applied Statistics (JAS)
This paper estimates disaggregated import demand function for Nigeria using annual data from 1970 to 2019. The study employs the Zivot-Andrews unit root and Gregory-Hansen cointegration tests to account for the role of structural breaks and the error correction mechanism for shortrun analysis, respectively. The results show that household consumption, industrial output and domestic investment are the major determinants of import demand for consumer, intermediate and investment goods, respectively. Furthermore, the import demand for investment goods is not sensitive to variations in relative prices. However, relative prices is negative and significant to import demand for consumer and intermediate goods. Exchange …
Size And Determinants Of The Shadow Economy In Nigeria: Evidence From A Monetary Approach,
2022
Central Bank of Nigeria
Size And Determinants Of The Shadow Economy In Nigeria: Evidence From A Monetary Approach, Tari M. Karimo, Mohammed M. Tumala, Ibrahim U, Wambai
CBN Journal of Applied Statistics (JAS)
Thiis study investigates the size and determinants of the shadow economy in Nigeria. It adopts an aggregation approach within the monetary framework and utilises the ARDL estimation technique to analyse quarterly data from 2010 Q1 to 2019 Q4. On average, the results suggest that the quarterly size of the shadow economy is about 55 per cent of the country’s GDP. The findings show that government size reduces the size of the shadow economy in the short run but increases it in the long run. The study also finds that interest rate, which is the opportunity cost of holding cash, and …
Fiscal And Monetary Policy Interactions In A Developing Economy: A Dsge-Based Evidence From Nigeria,
2022
Department of Economics and Development Studies, Covenant University, Nigeria.
Fiscal And Monetary Policy Interactions In A Developing Economy: A Dsge-Based Evidence From Nigeria, Queen E. Oye, Philip O. Alege
CBN Journal of Applied Statistics (JAS)
This study characterizes the nature of fiscal-monetary interaction in Nigeria and gauges its macroeconomic effects by estimating a New Keynesian Dynamic Stochastic General Equilibrium (NK DSGE) model. Two policy simulations were also conducted. The first experiment considers the desirable active-passive policy mix while the second experiment ranks alternative monetary policy rules among the differing objectives of price, output and exchange rate stabilization. The study finds that fiscal and monetary policies interact as complements in an active monetary and passive fiscal policy mix over the sample period. The result from the first policy simulation reveals that the active monetary and passive …
Market Risk Factors And Stock Returns In The Nigerian Bourse,
2022
Banking and Finance Department, Faculty of Management Sciences, University of Benin, Benin City, Nigeria
Market Risk Factors And Stock Returns In The Nigerian Bourse, Omorose A. Ogiemudia, Osagie Osifo, Igbinovia L. Eghosa
CBN Journal of Applied Statistics (JAS)
This study examines the link between market risk and equity return in Nigeria between 1980 to 2019. It employs the vector error correction model (VECM) to determine the short run dynamics and long run effect of market risk factors on stock return. The findings revealed that a dynamic relationship exists between market risk factors and stock returns in Nigeria. Also, exchange rate risk and oil price risks have significant influence on stock return, while inflation and interest rate risk, and political instability risks have a non-significant impact on stock return. Finally, a unidirectional relationship was detected between interest rate, oil …
Savings-Investment Gap In Sub-Saharan Africa: Does The Interaction Of Financial Sector Development And Migrant Remittances Matter?,
2022
Department of Economics, Faculty of Economics and Management Sciences, University of Ibadan, Nigeria.
Savings-Investment Gap In Sub-Saharan Africa: Does The Interaction Of Financial Sector Development And Migrant Remittances Matter?, Wasiu Adekunle, Oluwatosin Adeniyi, Joshua Afolabi, Musibau Babatunde, Edward Omiwale
CBN Journal of Applied Statistics (JAS)
This study analyses the interactive effects of migrant remittances and financial development on savings-investment gap for a panel of 18 Sub-Saharan Africa (SSA) countries from 1990-2017. Results from a panel ARDL model show that migrant remittances reduce savings-investment gap in the long run. The gap is further reduced when the individual effect of financial development, and the interactive effects of migrant remittances and financial development are taken into consideration. Further analysis reveals evidence of widening effects of rising real GDP growth and bank deposits over a long-term horizon, while higher private sector credit widened the savings-investment gap only in the …
Impact Of Exchange Rate On Trade Flow In Nigeria,
2022
Benue State University, Makurdi
Impact Of Exchange Rate On Trade Flow In Nigeria, Victor U. Ijirshar, Isa J. Okpe, Jerome T. Andohol
CBN Journal of Applied Statistics (JAS)
This study examines the impact of exchange rate on trade flow in Nigeria from 1986 to 2021. The study utilises linear and nonlinear autoregressive distributed lag (ARDL and NARDL) models to test the J-Curve hypothesis and the Marshall-Lerner condition in Nigeria. The study found symmetric effects of exchange rate on trade balance, exports, and imports. The findings also show that real exchange rate depreciation has a strong negative influence on trade balance and exports in the short run but positive in the long run, exhibiting the shape typology of the J-curve. Furthermore, the study reveals evidence of the Marshall-Lerner condition …
Mle And Eap Methods For Estimating Ability Scores For Data Of Varying Sample Size And Item Length,
2022
University of Arkansas, Fayetteville
Mle And Eap Methods For Estimating Ability Scores For Data Of Varying Sample Size And Item Length, Sahar Taji
Graduate Theses and Dissertations
In this research, the performance of two popular estimators, Maximum Likelihood Estimator(MLE) and Bayesian Expected a Posteriori (EAP) is studied and compared in estimating the latent ability score in an Item Response Theory (IRT) model. The 2-Parameter Logistic (2PL) IRT model which is characterized by difficulty and discrimination item parameters is used to estimate the latent ability scores. Several datasets are generated for variety of sample size and item length values. The Monte-Carlo simulation is used to analyze the performance of the estimators. Results show that MLE produces reliable results with low root mean square error (RMSE) across all datasets. …
