Statistical Methodology Commons^™

Analyses Of Effect Indices Across Single-Case Research Designs In Counseling, Cian L. Brown

Graduate Theses and Dissertations

Single case research design (SCRD) is a common methodology used across clinical disciplines to determine treatments effectiveness by comparing treatment conditions to baseline conditions in individual cases, usually among researchers working with smaller samples. Although popular within behavioral disciplines such as special education and behavioral analysis, studies have begun to emerge in counseling. However, guidance and current understanding of the use of SCRD in counseling is limited. A content analysis of counseling journals from 2003 to 2014 yielded only 7 studies using SCRD. In 2015, the flagship counseling journal, Journal of Counseling and Development, published a special issue on the …

Generalized Ratio-Product Cum Regression Variance Estimator In Two-Phase Sampling, Isah Muhammad

CBN Journal of Applied Statistics (JAS)

This study develops a flexible and efficient generalized ratio-product cum regression type estimator of population variance utilizing auxiliary variable in two-phase sampling that incorporates the properties of ratio-type and product-type estimators. The properties of the estimator were derived using first order approximation. The theoretical conditions under which the precision and the flexibility of the estimator is better than some classical estimators are also provided. Empirical evidence from five real datasets suggests that the proposed estimator outperforms the classical variance, ratio variance, product, and exponential ratio type estimators in terms of precision and efficiency. The estimator can be utilized to provide …

Modelling The Naira Exchange Rate Dependence Using Static And Time-Varying Copula, Kabir Katata

CBN Journal of Applied Statistics (JAS)

This paper examines the dependence structure of different currencies versus the Nigerian Naira using constant and time-varying copula. Daily Naira/USD, Naira/Yuan, Naira/Pound, and Naira/Euro exchange rates from 23 December 2011 to 12 May 2020 were utilised. We fitted eight constant and time-varying copula families using the exchange rate standardised residuals. The study finds that the Naira exchange rate may be estimated with student t-copula, Symmetrized Joe-Clayton (SJC), or Rotated Gumbel copula models and Autoregressive (AR)– Glosten Jagannathan RunkleGeneralized Autoregressive Conditional Heteroscedastic (GJR-GARCH) (1,1) models with skewed t residuals for margins. The Naira exchange rate returns is timevarying, tail-dependent, and asymmetric. …

Bayesian Strategies For Propensity Score Estimation In Causal Inference., Uthpala I. Wanigasekara

Electronic Theses and Dissertations

Causal inference is a method used in various fields to draw causal conclusions based on data. It involves using assumptions, study designs, and estimation strategies to minimize the impact of confounding variables. Propensity scores are used to estimate outcome effects, through matching methods, stratification, weighting methods, and the Covariate Balancing Propensity Score method. However, they can be sensitive to estimation techniques and can lead to unstable findings. Researchers have proposed integrating weighing with regression adjustment in parametric models to improve causal inference validity. The first project focuses on Bayesian joint and two-stage methods for propensity score analysis. Propensity score modeling …

The Private Pilot Check Ride: Applying The Spacing Effect Theory To Predict Time To Proficiency For The Practical Test, Michael Scott Harwin

Theses and Dissertations

This study examined the relationship between a set of targeted factors and the total flight time students needed to become ready to take the private pilot check ride. The study was grounded in Ebbinghaus’s (1885/1913/2013) forgetting curve theory and spacing effect, and Ausubel’s (1963) theory of meaningful learning. The research factors included (a) training time to proficiency, which represented the number of training days needed to become check-ride ready; (b) flight training program (Part 61 vs. Part 141); (c) organization offering the training program (2- or 4-year college/university vs. FBO); (d) scheduling policy (mandated vs. student-driven); and demographical variables, which …

Exploration And Statistical Modeling Of Profit, Caleb Gibson

Undergraduate Honors Theses

For any company involved in sales, maximization of profit is the driving force that guides all decision-making. Many factors can influence how profitable a company can be, including external factors like changes in inflation or consumer demand or internal factors like pricing and product cost. Understanding specific trends in one's own internal data, a company can readily identify problem areas or potential growth opportunities to help increase profitability.

In this discussion, we use an extensive data set to examine how a company might analyze their own data to identify potential changes the company might investigate to drive better performance. Based …

Bayesian Learning Of Spatiotemporal Source Distribution For Beached Microplastic In The Gulf Of Mexico, David Pojunas

Graduate Theses and Dissertations

Over the last several decades, plastic waste has gradually accumulated while slowly degrading in terrestrial and oceanic environments. Recently, there has been an increased effort to identify the possible sources of plastic to understand how they affect vulnerable beaches. This issue is of particular concern in the Gulf of Mexico due to the presence of oil, natural gas, and plastic production. In this thesis, we expand upon existing Bayesian plastic attribution models and develop a rigorous statistical framework to map observed beached microplastics to their sources. Within this framework, we combine Lagrangian backtracking simulations of floating particles using nurdle beaching …

A Bayesian Network-Based Methodology For Improved Bridge Load Rating And Asset Management, Jeffery Mark Roberts

Dissertations and Theses

From the day a new structure is made available for use, to the day that the structure is no longer able to fulfill an intended purpose, structural safety is a vital interest. Managing a portfolio of structures can be a difficult undertaking for an asset manager, particularly if different types of structures are being maintained. The goal is to manage assets in the most efficient manner which can be influenced by, at a minimum, safety and financial concerns.

A potential tool for an asset manager or owner is the use of Bayesian Networks (BNs). When a BN is used to …

Statistical And Machine Learning Approaches To Describe Factors Affecting Preweaning Mortality Of Piglets, Md Towfiqur Rahman, Tami M. Brown-Brandl, Gary A. Rohrer, Sudhendu R. Sharma, Vamsi Manthena, Yeyin Shi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

High preweaning mortality (PWM) rates for piglets are a significant concern for the worldwide pork industries, causing economic loss and well-being issues. This study focused on identifying the factors affecting PWM, overlays, and predicting PWM using historical production data with statistical and machine learning models. Data were collected from 1,982 litters from the United States Meat Animal Research Center, Nebraska, over the years 2016 to 2021. Sows were housed in a farrowing building with three rooms, each with 20 farrowing crates, and taken care of by well-trained animal caretakers. A generalized linear model was used to analyze the various sow, …

A Classical Fall Statistics Problem, Timothy Meyer

Cornhusker Economics

An evaluation of traditional baseball measures and suggestions for alternatives, centering on statistics related to the offensive quality of a player.

Summarization Of Reliability Theory For Condition Assessment Of Brige Structurs, Peng Jianxin, Chai Ying, Zhang Jianren

Journal of China & Foreign Highway

This paper briefly reviewed the principles and development of structural design theories, and summarized the current research of structural reliability theories. Meanwhile, various applicable methods of reliability theories were finely described and analyzed, with the latest progress in structural reliability analysis and reliability-based design optimization outlined. Additionally, the uncertainty propagation methods and reliability assessment methods were analyzed, and the development trend of structural reliability was summarized, which can provide a summary and reference for future researchers to study structural reliability.

Study On Laws Of Surface Movement A Nd Deformation Of Goaf Under Subgrade In Sand-Loess Area, Lei Mingxuan, Liu Guotian, Su Weiwei, Zhang Liujun, Yin Lihua

Journal of China & Foreign Highway

A large number of goaf under sand-loess areas in China greatly restrict the highway construction development in sand-loess areas. Meanwhile, the goaf evaluation beneath under subgrade in sand-loess areas is especially important. According to the characteristics of goaf beneath the highway of sand-loess areas, based on FLAC3D software, this paper selected reasonable parameters to build the model of goaf under subgrade. Additionally, based on the mechanical property analysis of sand loess, the laws of surface movement and deformation parameters of the goaf under the subgrade were summarized, and the surface movement and deformation areas were identified, with the range of …

Exploring Long-Term Protective Effect Of High Vertical Sand Barrier On Top Of Complex Longitudinal Sand Ridge In Taklamakan Desert, Jin Changning

Journal of China & Foreign Highway

By taking the high vertical sand barriers deployed on the top of the complex longitudinal sand ridges in the hinterland of Taklamakan Desert as the object, this paper investigated the sand protection effect from the long-term perspective on the basis of several years’ comparative observation. The result analysis shows that in addition to the recognized sand blocking effect, high vertical sand barriers also have a more important role of sand fixation, which means that the barriers can change the original overall movement of sand dunes into only the falling sand slope forward, with the windward slopes basically fixed. Even if …

Experimental Study On Dynamic Resilient Modulus Of Cement-Improved Fine-Grained Soils In Wet Subgrade, Huang Chongwei, Zhu Baobing, Zhang Yi, Sun Yu, Guo Dandan

Journal of China & Foreign Highway

To investigate the design and construction of wet subgrade in southern China, this paper selected three typical soil samples of the new highway subgrade of Ecological Avenue in Chongming District, Shanghai, and improved the samples by cement disposal technology. Meanwhile, the effects of the water content, degree of compaction, cement content, age of maintenance and stress state on the dynamic resilient modulus were analyzed by experimental methods. The results show that the effects of cement content, water content and age of maintenance on the dynamic resilient modulus of three kinds of cement-improved fine-grained soil in wet subgrade are larger, and …

Study On Stability Analysis And Treatment Of A Expressway Landslide, Huang Hongchao

Journal of China & Foreign Highway

In highway construction of mountainous areas, landslides are easily triggered due to the complex geological conditions, thereby causing serious economic loss and even casualties. Therefore, the study of landslide treatment schemes has caught increasingly more attention from scholars. By taking the giant landslide treatment on a highway of southeastern Yunnan as an example, this paper analyzed the process and cause of giant landslide formation, and then conducted inverse calculations to determine the stability analysis parameters of landslides via combining the topography and geology and slope state before and after slope excavation. Finally, according to the calculation results of the residual …

Discussion On Treatment Scheme Of Soft Foundation Based On Cooperative Deformation Of Roadbed And Frame Structure, Liu Jizhong, Chen Kai, Yang Fengyu

Journal of China & Foreign Highway

In view of insufficient consideration of cooperative roadbed and structure deformation, by taking the soft foundation with frame structures in the fill roadbed as the research object, this paper adopted Midas GTS NX finite element analysis software to simulate the pavement settlement and plastic zone distribution of the soft foundation treated by cast-in-place piles. Considering that the stiffness difference between the roadbed and the frame structure can easily result in pavement cracking, a variable stiffness composite foundation treatment optimization scheme was proposed. This scheme coordinated the cooperative settlement and deformation of the roadbed and frame structure, and prevented the development …

Study On Key Technology Of Landslide Investigation And Treatment Plan Of Coal Stratum In Section K 132 Of A Highway, Wei Dongxu, Wang Guanguo, Li Jian, Zheng Guosheng

Journal of China & Foreign Highway

Coal strata feature soft lithology, low strength and easy softening under contact with water. During the subgrade excavation, the slopes of the coal strata often form a potential slip surface, which can control the stability of the overall slope. By taking the K132 landslide of Longchuan-Huaiji Expressway as an example, this paper comprehensively determined the characteristics of the landslide in coal strata, especially the characteristics of slip surfaces, by adopting the high-density resistivity and deep-hole displacement monitoring methods and combining geological drilling. The stability analysis results show that the carry-over factor method and Geoslope analysis can calculate the residual sliding …

Feasibility Study Of Pavement Rutting Evaluation Method Based On Driving Vibration, Zhang Jinxi, Wang Peirong, Cao Dandan, Ceng Jingxiang

Journal of China & Foreign Highway

To explore the intelligent detection and monitoring methods of pavement performance, this paper utilized the self-developed driving data collection app to collect vibration acceleration and other data of the pavement during driving, and carried out the feasibility study of evaluating the pavement rutting by driving vibration. Firstly, the collected vibration acceleration data was processed for noise reduction, and the driving vibration characteristics in different working conditions were analyzed. Secondly, seven time domain indicators with high correlation between vibration acceleration and the rutting were extracted as the initial set of indicators, and the seven indicators were downscaled into two independent principal …

Study On Influence Factors Of Temperature Field Of Crc+Ac Composite Road Surface, Cheng Xiaoliang, Zhang Hao, Li Sheng

Journal of China & Foreign Highway

In view of the factors influencing the temperature field of CRC+AC composite road surfaces, this paper analyzed the temperature field distribution and influencing factors of CRC+AC composite road surface structures based on the meteorology and heat transfer theories, and conducted 3D solid modeling and numerical simulation by adopting Abaqus finite element software. The results show that in certain conditions, the deeper distance from the road surface leads to smaller temperature change of the road surface structure. When the depth exceeds 0.6 m, the temperature is almost unchanged and has little difference with the outside ambient temperature. By increasing the thermal …

Design Of Polymer Optical Fiber Icing Sensor And Detection Method Of Road Ice Thickness, Xie Qingzhong, Wang Ling, Ge Jingyong, Shi Ning, Zhang Jiupeng

Journal of China & Foreign Highway

To detect the icing condition and icing thickness of asphalt pavement in extreme weather conditions, this paper firstly compared the performance indexes of polymer optical fiber and quartz optical fiber, chose polymer optical fiber as the optical transmission medium, and selected the distribution mode of coaxial sensor probes. Meanwhile, it designed the weak signal detection circuit and finally completed the design of a polymer optical fiber road icing sensor. Secondly, it was verified that the effect of temperature on the icing detection results was negligible, and icing tests under different light intensities were conducted under simulated light, with the icing …