Social and Behavioral Sciences Commons^™

A Monte Carlo Analysis Of Ordinary Least Squares Versus Equal Weights, James Brewer Ayres

Masters Theses & Specialist Projects

Equal weights are an alternative weighting procedure to the optimal weights offered by ordinary least squares regression analysis. Also called units weights, equal weights are formed by standardizing scores on the predictor variables and averaging these standardized scores to create a composite score. Research is limited regarding the conditions under which equal weights result in cross-validated 𝑅𝑅2 values that meet or exceed optimal weights. In this study, I explored the effect of various predictor-criterion correlations, predictor intercorrelations, and sample sizes to determine the relative performance of equal and optimal weighting schemes upon cross-validation. Results indicated that optimally weighted predictors explained …

Anxious And Oppositional Behavior Factors In A Community Sample Of Youth With Selective Mutism, Andrew Gerthoffer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Selective mutism (SM) is a childhood disorder characterized by a failure to speak in certain situations (e.g., school, social situations; APA, 2013). SM is best assessed using a comprehensive multimodal strategy (Dow et al., 1995; Krysanski, 2003; Viana et al., 2009; Wong, 2010), including parent reports of a child’s behavior. One commonly used parent report measure is the Child Behavior Checklist (CBCL; Achenbach & Rescorla, 2001). The purpose of the present study was to identify specific CBCL items that may help substantiate SM subtypes in children. The study used confirmatory factor analysis to determine whether a two-factor structure (anxious and …

Intra-Field Canopy Nitrogen Retrieval From Unmanned Aerial Vehicle Imagery For Wheat And Corn Crops In Ontario, Canada, Hwang Lee

Electronic Thesis and Dissertation Repository

The optimization of crop nitrogen fertilization to accurately predict and match the nitrogen (N) supply to the crop N demand is the subject of intense research due to the environmental and economic impact of N fertilization. Excess N could seep into the water supplies around the field and cause unnecessary spending by farmers. Understanding the detailed spatial information about a crop status is known as a farming management technique called precision agriculture, which allows farmers to maximize their yield and profit while reducing the inputs of fertilizers, pesticides, water, and insecticides.

The goal of this study is to document and …

Hoop Dreams: An Empirical Analysis Of The Gender Wage Gap In Professional Basketball, Hailey Dicicco

Business and Economics Presentations

The gender wage gap is a very prominent point of discussion in the professional world, but in the sports world, it has taken the spotlight in recent years. One sport that has seen discussion and debate over salary differences is the National Basketball Association and Women’s National Basketball Association. In 2018, the average salary in the NBA was 6.4 million dollars, while the average salary in the WNBA was 71,635 dollars. A reason why these salaries are so differently is due to the amount of revenue that each league brings in. The NBA brings in roughly 7.4 billion dollars a …

How Did Medicaid Expansion Affect The Provider Labor Market?, Aaron Wu

Honors Theses

One provision of the Affordable Care Act was to expand Medicaid eligibility for a greater number of low-income patients. The resulting increase in demand for care was largely explored, but the effect of the 2014 Medicaid expansion on the physician and advanced practitioner labor market has not been well researched by economists. Using pooled cross-sectional data from the 2010 – 2018 American Community Surveys, this paper examines whether the Medicaid expansion has caused notable changes in physician, physician assistant, and nurse practitioner hours, compensation, and overall employment. The literature shows that practices that employ nurse practitioners are far more likely …

Examining The Impact Of It Investment On Insurer Productivity: A Bootstrapped Malmquist Frontier Analysis Approach, Jee Yuen Yew

Dissertations and Theses Collection (Open Access)

This paper attempts to examine productivity changes of insurance companies in Singapore as represented by bootstrapped Malmquist indices, generated from a data envelopment analysis (DEA)-based frontier analysis, and attribute these changes to an increasing investment in information technology infrastructure and equipment, and increasing investment in staff enhancement. Through this analysis, the author finds that there has been a general increase in productivity and efficiency from 2011 – 2017, as seen from changes in the kernel density functions of productivity change between the two periods. The author also finds, through running a panel tobit regression model, that there is a positive …

Marriage And Cohabitation In The United States: The Effects Of Union Type On Relationship Quality., Courtney M. Lush

Electronic Theses and Dissertations

Using national dyadic data from the 2010 Married and Cohabiting Couples (MCC) survey, I examine the effects on relationship quality of union type: “direct marriage”, “marriage after cohabiting”, “cohabitation with plans to marry”, “cohabitation with no marriage plan”. In addition, I examine whether these effects are different for men and women. Consistent with prior research, I found that cohabitors without plans to marry report the lowest levels of relationship quality and those who married directly report the highest levels of relationship quality. Also consistent with prior research, I find no gendered differences in the effect of union type on relationship …

An Exploration Of Link Functions Used In Ordinal Regression, Thomas J. Smith, David A. Walker, Cornelius M. Mckenna

Journal of Modern Applied Statistical Methods

The purpose of this study is to examine issues involved with choice of a link function in generalized linear models with ordinal outcomes, including distributional appropriateness, link specificity, and palindromic invariance are discussed and an exemplar analysis provided using the Pew Research Center 25th anniversary of the Web Omnibus Survey data. Simulated data are used to compare the relative palindromic invariance of four distinct indices of determination/discrimination, including a newly proposed index by Smith et al. (2017).

Prospects For Commercialization Among Smallholder Farmers In South Africa: A Case Study, Christopher Ugochukwu Nwafor, Carlu Van Der Westhuizen

Journal of Rural Social Sciences

The study explored determinants of commercialization among selected smallholder potato farmers in Bizana, Eastern Cape Province of South Africa. Increasingly presented as a rural development paradigm, the capability of many smallholders to commercialize is questioned. Fifty-eight smallholder farmers were purposively sampled for this study, which estimated farmers’ level of commercialization and identified factors contributing to their estimated engagement with markets. Structured questionnaires were used to obtain primary data from farmers, while reports from published materials were also reviewed. The study utilized the household commercialization index (HCI) and ordinary least squares (OLS) regression model as its main analytical tools. It found …

Effects Of Nano-Clay Content, Foaming Temperature And Foaming Time On Density And Cell Size Of Pvc Matrix Foam By Presented Least Absolute Shrinkage And Selection Operator Statistical Regression Via Suitable Experiments As A Function Of Mmt Content, Zhixiong Li, Hamzeh Shahrajabian, Seyed Amin Bagherzadeh, Hamid Jadidi, Arash Karimipour, Iskander Tlili

Faculty of Engineering and Information Sciences - Papers: Part B

Present article aims to investigate the effect of nano-clay content, foaming temperature and foaming time on the density and cell size of the PVC matrix foam. The cell size would affect the insulating and mechanical properties. The foaming temperature is set in three levels of 70, 80 and 90 °C, foaming time is set in three levels of 10, 20, and 30 s; and nano-clay is in content of 1, 3, and 5 wt%. Outputs consist the density and cell size, which affect impact the thermal conductivity, mechanical properties and the weight of the polymer foam. In addition the Least …

Does Racial Discrimination Exist In The Nba?, Logan Kendall

Williams Honors College, Honors Research Projects

This paper aims to examines the affect of race on compensation for NBA players. Based on prior research, I pose the hypothesis that racial discrimination does exist in the NBA with there being a premium for white players. A second hypothesis I present based on the previous research is that the premium for white players exist for only some groups of players and for other groups there with not exist discrimination based on player race. By using career data from every player who played in the 2019-2020 NBA season and their 2019-2020 salaries, a few different models where ran. The …

Spatial Patterns Of Adverse Birth Outcomes Among Black And White Women In Massachusetts – The Role Of Population-Level And Individual-Level Factors, Yelena Ogneva-Himmelberger, Madeline Haynes

Sustainability and Social Justice

This study explores spatial distribution of adverse birth outcomes (ABO), defined as low birth weight (<=2500 g) and preterm deliveries (gestational age <37 weeks), in black and white mothers in the state of Massachusetts, USA. It uses 817877 individual birth records from 2000-2014 aggregated to census tracts (census enumeration unit with population of approximately 4500 people). To account for small numbers of births in some tracts, an Empirical Bayes smoother algorithm is used to calculate ABO rates. The study applies ordinary least squares (OLS) and spatial regression to examine the relationship between ABO rates, seven individual-level factors from birth certificates and nine population-level factors (income level, education level, race) from census data. Explanatory power of these factors varies between the two races. In models based only on individual-level factors, all seven factors were significant (p<0.05) in the black mothers’ model while only three were significant in the white mothers’ model. Models based only on population-level variables produced better results for the white mothers than for black mothers. Models that included both individual and population-level variables explained 40% and 29% of ABO variance for black and white women respectively. The findings from this study give health-care providers and health-care policy-makers important information regarding ABO rates and the contributing factors at a local level, thus enabling them to isolate specific areas with the highest need for targeted interventions.

Tolerance Intervals For Time Series Models And Specifying Trimming/Winsorizing Cutoffs, Kedai Cheng

Theses and Dissertations--Statistics

Confidence intervals are used to capture a parameter of interest, usually a mean or a quantile, at a specified confidence level. Prediction intervals are another practical interval that aim at making sound predictions of future values with some confidence. Although these are useful inference tools, neither of them gives people a plausible range of the sampled population. Tolerance intervals are such an inference tool that captures a specified proportion of the sampled population at a predetermined confidence level. In this dissertation, tolerance intervals for an autoregressive process with order p are constructed. In addition, a method of utilizing tolerance interval …