Design of Experiments and Sample Surveys Commons^™

Adaptive Randomization Designs, Jenna Colavincenzo

Statistics

Adaptive design methodologies use prior information to develop a clinical trial design. The goal of an adaptive design is to maintain the integrity and validity of the study while giving the researcher flexibility in identifying the optimal treatment. An example of an adaptive design can be seen in a basic pharmaceutical trial. There are three phases of the overall trial to compare treatments and experimenters use the information from the previous phase to make changes to the subsequent phase before it begins.

Adaptive design methods have been in practice since the 1970s, but have become increasingly complex ever since. One …

Blunt Impact Performance Evaluation Of Helmet Lining Systems For Military And Recreational Use, Jaclyn Siniora, Ryan Taylor, Darren Suey

Industrial Technology and Packaging

With the increasing problem in collegiate athletes experiencing injuries to the brain, different helmet liners where put to the test to see which liner provided athletes the greatest protection under specific conditions.

This senior project evaluates five different liners in football helmets. Each of the helmet liners were tested at three different temperatures: hot, cold, and ambient. Each helmet had seven different impact locations which were put to the test. The project was designed to be used to test ACH military combat liners as well. Due to shipping bottle necks the ACH combat liners have been left to future Cal …

Estimating The Impact Of Community-Level Interventions: The Search Trial And Hiv Prevention In Sub-Saharan Africa, Laura Balzer, Maya Petersen, Joshua Schwab, Mark Van Der Laan

Laura B. Balzer

Evaluation of community level interventions to prevent HIV infection presents significant methodological challenges. Even when it is feasible to randomly assign a treatment versus control level of the intervention to each community in a sample, measurement of incident HIV infection remains difficult. In this talk we describe an experimental design developed for the SEARCH Trial, a large community randomized trial that will evaluate the impact of expanded treatment on incident HIV and other outcomes. Regular community-wide testing campaigns are conducted and a random sample of community members who fail to attend a campaign are tracked. The data generated by this …

Why Match In Individually And Cluster Randomized Trials?, Laura B. Balzer, Maya L. Petersen, Mark J. Van Der Laan

Laura B. Balzer

The decision to match individuals or clusters in randomized trials is motivated by both practical and statistical concerns. Matching protects against chance imbalances in baseline covariate distributions and is thought to improve study credibility. Matching is also implemented to increase study power. This article compares the asymptotic efficiency of the pair-matched design, where units are matched on baseline covariates and the treatment randomized within pairs, to the independent design, where units are randomly paired and the treatment randomized within pairs. We focus on estimating the average treatment effect and use the efficient influence curve to understand the information provided by …

Using The R Library Rpanel For Gui-Based Simulations In Introductory Statistics Courses, Ryan M. Allison

Statistics

As a student, I noticed that the statistical package R (http://www.r-project.org) would have several benefits of its usage in the classroom. One benefit to the package is its free and open-source nature. This would be a great benefit for instructors and students alike since it would be of no cost to use, unlike other statistical packages. Due to this, students could continue using the program after their statistical courses and into their professional careers. It would be good to expose students while they are in school to a tool that professionals use in industry. R also has powerful …

The Efficacy Of An Audio Program And Discussion Guide In Promoting Exclusive Breastfeeding In Cameroon, Africa, Kathryn R. Reinsma

Loma Linda University Electronic Theses, Dissertations & Projects

Background: In the Northwest Region of Cameroon, approximately 90% of women initiate breastfeeding; however, only 34% continue exclusive breastfeeding for the recommended six months (Kakute, et al., 2005; WHO, 2008). Entertainment-education is a mass-media communication strategy of placing educational information into media such as television programs, movies, and radio programs (Siegel & Lotenberg, 2007). This form of behavioral change communication has proven effective in addressing health-related issues in developing countries.

Purpose: The aim was to design an audio program and discussion guide to test the hypothesis that an audio program and discussion guide improves exclusive breastfeeding knowledge, beliefs, benefits, self-efficacy, …

Why Match In Individually And Cluster Randomized Trials?, Laura Balzer, Maya Petersen, Mark Van Der Laan

Laura B. Balzer

The decision to match individuals or clusters in randomized trials is motivated by both practical and statistical concerns. Matching protects against chance imbalances in baseline covariate distributions and is thereby thought to improve study credibility. Matching is also implemented to increase study power. Analogue to Rose and van der Laan (2009), this article investigates the asymptotic efficiency of pair-matching individuals or clusters relative to not matching in randomized trials. We focus on estimating the average treatment effect. We use the efficient influence curve to understand the information provided by each design for estimation of the target causal parameter. Our approach …

Sample Size Calculations For Roc Studies: Parametric Robustness And Bayesian Nonparametrics, Dunlei Cheng, Adam J. Branscum, Wesley O. Johnson

Dunlei Cheng

Methods for sample size calculations in ROC studies often assume independent normal distributions for test scores among the diseased and non-diseased populations. We consider sample size requirements under the default two-group normal model when the data distribution for the diseased population is either skewed or multimodal. For these two common scenarios we investigate the potential for robustness of calculated sample sizes under the mis-specified normal model and we compare to sample sizes calculated under a more flexible nonparametric Dirichlet process mixture model. We also highlight the utility of flexible models for ROC data analysis and their importance to study design. …

Planned Missingness Study Design: Two Methods To Developing The Study Survey Versions, E. Whitney G. Moore

Kinesiology, Health and Sport Studies

A planned missingness data study design takes advantage of modern techniques for handling data missingness that is MCAR (Missing Completely at Random) and MAR (Missing at Random) (Brown, 2006; Enders, 2010). As modern data imputation techniques have improved, this study design option has become a powerful, cost-effective option for collecting the most data across the largest sample possible, while keeping the fatigue effect and expense of the study minimized (Little, 2010a, 2010b, 2012). The purpose of this guide is to provide an applied example for designing the surveys necessary when conducting a planned missingness research study design.

The Dirty “S” Word: Innovative Teaching Techniques For Counselor Educators Facilitating Learning In Statistics And Research, Rebecca L. Tadlock-Marlo, Megan Michalak

Rebecca L Tadlock-Marlo

Innovative pedagogy will be presented and discussed to help make research a less painful class to both teach and learn. Foci include teaching methods, potential assignments, and suggestions for activities to help facilitate a more fluid learning process for counselors. Attendees will explore aspects of helping students overcome their fear of both statistics and research.

The Dirty “S” Word: Innovative Teaching Techniques For Counselor Educators Facilitating Learning In Statistics And Research, Rebecca Tadlock-Marlo, Megan Michalak

Faculty Research & Creative Activity

Innovative pedagogy will be presented and discussed to help make research a less painful class to both teach and learn. Foci include teaching methods, potential assignments, and suggestions for activities to help facilitate a more fluid learning process for counselors. Attendees will explore aspects of helping students overcome their fear of both statistics and research.

A General Family Of Dual To Ratio-Cum-Product Estimator In Sample Surveys, Florentin Smarandache, Rajesh Singh, Mukesh Kumar, Pankaj Chauhan, Nirmala Sawan

Branch Mathematics and Statistics Faculty and Staff Publications

This paper presents a family of dual to ratio-cum-product estimators for the finite population mean. Under simple random sampling without replacement (SRSWOR) scheme, expressions of the bias and mean-squared error (MSE) up to the first order of approximation are derived. We show that the proposed family is more efficient than usual unbiased estimator, ratio estimator, product estimator, Singh estimator (1967), Srivenkataramana (1980) and Bandyopadhyaya estimator (1980) and Singh et al. (2005) estimator. An empirical study is carried out to illustrate the performance of the constructed estimator over others.

A Framework For Generating Data To Simulate Application Scoring, Kenneth Kennedy, Sarah Jane Delany, Brian Mac Namee

Conference papers

In this paper we propose a framework to generate artificial data that can be used to simulate credit risk scenarios. Artificial data is useful in the credit scoring domain for two reasons. Firstly, the use of artificial data allows for the introduction and control of variability that can realistically be expected to occur, but has yet to materialise in practice. The ability to control parameters allows for a thorough exploration of the performance of classification models under different conditions. Secondly, due to non-disclosure agreements and commercial sensitivities, obtaining real credit scoring data is a problematic and time consuming task. By …

Music And Radio Preferences On The Cal Poly Campus, Rory Bloch

Statistics

No abstract provided.

Factors That Inhibit Or Enhance Maternal Coping With Stillbirth In Chhattisgarh, India, Lisa R. Roberts

Loma Linda University Electronic Theses, Dissertations & Projects

Background: Over half of the known stillbirths occur in four highly populated countries—India among them. While acknowledged as a significant public health issue in western societies, little is known about maternal coping with stillbirth in developing countries. The purpose of this mixed methods study is to explore how issues of gender and power, social support, coping efforts, and religious beliefs influence perinatal grief outcomes among poor women in rural Chhattisgarh, India.

Methods: In Phase 1 of this mixed methods study, grounded theory methods were used to explore perceptions regarding stillbirth. A de-identified medical records review of 536 deliveries at Christian …

Relationship Between Perceived And Actual Quality Of Data Checking, Hunter Speich, Sophia Karas, Dan Erosa, Kelly Grob, Kimberly A. Barchard

Festival of Communities: UG Symposium (Posters)

Data quality is critical to reaching correct research conclusions. Researchers attempt to ensure that they have accurate data by checking the data after it has been entered. Previous research has demonstrated that some methods of data checking are better than others, but not all researchers use the best methods. Perhaps researchers continue to use less optimal data checking methods because they mistakenly believe that they are highly accurate. The purpose of this study was to examine the relationship between perceived data quality and actual data quality. A total of 29 participants completed this study. Participants checked that letters and numbers …

Estimation And Testing In Targeted Group Sequential Covariate-Adjusted Randomized Clinical Trials, Antoine Chambaz, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

This article is devoted to the construction and asymptotic study of adaptive group sequential covariate-adjusted randomized clinical trials analyzed through the prism of the semiparametric methodology of targeted maximum likelihood estimation (TMLE). We show how to build, as the data accrue group-sequentially, a sampling design which targets a user-supplied optimal design. We also show how to carry out a sound TMLE statistical inference based on such an adaptive sampling scheme (therefore extending some results known in the i.i.d setting only so far), and how group-sequential testing applies on top of it. The procedure is robust (i.e., consistent even if the …

Developing A Library Value Indicator For A Disciplinary Population, Jeanne M. Brown

Library Faculty Publications

Three different ways of documenting library value were presented to fourth year landscape architecture students in the UNLV School of Architecture: a contingent valuation survey, a library calculator, and a survey to rate importance and impact of library services and features. Students used the three approaches, then discussed their experiences with the author. Their input suggested improvements in the instruments and provided feedback on possible positive and negative consequences of inviting this kind of valuing. Working with a focused collection and population provided a relatively safe environment to explore concerns about negative consequences.

Some Problems And Solutions In The Experimental Science Of Technology: The Proper Use And Reporting Of Statistics In Computational Intelligence, With An Experimental Design From Computational Ethnomusicology, Mehmet Vurkaç

Systems Science Friday Noon Seminar Series

Statistics is the meta-science that lends validity and credibility to The Scientific Method. However, as a complex and advanced Science in itself, Statistics is often misunderstood and misused by scientists, engineers, medical and legal professionals and others. In the area of Computational Intelligence (CI), there have been numerous misuses of statistical techniques leading to the publishing of insupportable results, which, in addition to being a problem in itself, has also contributed to a degree of rift between the Statistics/Statistical Learning community and the Machine Learning/Computational Intelligence community. This talk surveys a number of misuses of statistical inference in CI settings, …

How Other Drivers’ Vehicle Characteristics Influence Your Driving Speed, Russell Brockett

CMC Senior Theses

An analysis of the effect of passing vehicles’ characteristics and their impact on other drivers’ velocities was investigated. Three experimental studies were proposed and likely outcomes were discussed. Experiment 1 focused on the effect of passing vehicle type (SUV, sedan or truck) on driver speed. Drivers were hypothesized as going faster when the same vehicle type as they were driving passed them versus when no vehicle or a different vehicle passed them. Experiment 2 focused on the effect of passing SUV age on driver’s speed. Evidence suggests passing older SUVs will increase the driver’s speed more than new SUVs. Experiment …

A Guide To Defining And Implementing Protocols For The Welfare Assessment Of Laboratory Animals: Eleventh Report Of The Bvaawf/Frame/Rspca/Ufaw Joint Working Group On Refinement, P. Hawkins, D. B. Morton, O. Burman, N. Dennison, P. Honess, M. Jennings, S. Lane, V. Middleton, J. V. Roughan, S. Wells, K. Westwood

Research Methodology and Laboratory Animals Collection

The refinement of husbandry and procedures to reduce animal suffering and improve welfare is an essential component of humane science. Successful refinement depends upon the ability to assess animal welfare effectively, and detect any signs of pain or distress as rapidly as possible, so that any suffering can be alleviated. This document provides practical guidance on setting up and operating effective protocols for the welfare assessment of animals used in research and testing. It sets out general principles for more objective observation of animals, recognizing and assessing indicators of pain or distress and tailoring these to individual projects. Systems for …

Assessing The Necessity Of Chimpanzee Experimentation, Andrew Knight

Experimentation Collection

No abstract provided.

Uniform And Partially Uniform Redistribution Rules, Florentin Smarandache, Jean Dezert

Branch Mathematics and Statistics Faculty and Staff Publications

This short paper introduces two new fusion rules for combining quantitative basic belief assignments. These rules although very simple have not been proposed in literature so far and could serve as useful alternatives because of their low computation cost with respect to the recent advanced Proportional Conflict Redistribution rules developed in the DSmT framework.

Studies In Sampling Techniques And Time Series Analysis, Florentin Smarandache, Rajesh Singh

Branch Mathematics and Statistics Faculty and Staff Publications

This book has been designed for students and researchers who are working in the field of time series analysis and estimation in finite population. There are papers by Rajesh Singh, Florentin Smarandache, Shweta Maurya, Ashish K. Singh, Manoj Kr. Chaudhary, V. K. Singh, Mukesh Kumar and Sachin Malik. First chapter deals with the problem of time series analysis and the rest of four chapters deal with the problems of estimation in finite population. The book is divided in five chapters as follows: Chapter 1. Water pollution is a major global problem. In this chapter, time series analysis is carried out …

Some Ratio Type Estimators Under Measurement Errors, Florentin Smarandache, Mukesh Kumar, Rajesh Singh, Ashish K. Singh

Branch Mathematics and Statistics Faculty and Staff Publications

This article addresses the problem of estimating the population mean using auxiliary information in the presence of measurement errors.

An Investigation Of Process Parameters To Optimize The Fiber Diameter Of Electrospun Vascular Scaffolds Through Experimental Design, Steffi Wong

Biomedical Engineering

No abstract provided.

Developing A Library Value Indicator For A Disciplinary Population, Jeanne M. Brown

Library Faculty Presentations

Population
- Landscape architecture studio of ten 5th year students
- Use of physical library ranges from 1- 30 times/month
- Use of virtual library ranges from 2-30x/month
- Compared to others in School of Architecture use is moderate
- They self-rate as average or above average on library skills, compared to their peers

Facial Type Analysis Comparison Between Mri, Cbct, And Lateral Cephalometrics, Matthew A. Sanders

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Single Cephalometric measurements are comparable between Cone Beam Computed Tomography (CBCT), Magnetic Resonance Imaging (MRl) and Conventional Lateral Cephalometric (LC) imaging methods. This study evaluated the agreement between the three imaging methods in facial type analysis (using a composite of 5 cephalometric measures).

Methods and Materials: Twenty-two subjects participated in this study. Cranial images were generated via three modalities: LC, CBCT and MRl. Cephalometric landmarks were identified on the three images per subject and a facial type analysis performed. An equally weighted facial type calculation composed of 5 cephalometric measurements (facial axis, facial depth, mandibular plane, lower face height, …

A Critical Constructionist View Of "At-Risk" Youth In Alternative Education, Rachelle Silverstein Touzard

Loma Linda University Electronic Theses, Dissertations & Projects

Family therapists and school counselors are increasingly called upon to provide services for youth in alternative education (Carver, Lewis, & Tice, 2010). Alternative education systems are programs for youth who have been defined as at risk. This study explored the at-risk discourse and asked the questions (a) how do youth and staff define the term at risk, (b) construct their experience in alternative education systems, and (c) experience their relationships with each other.

Combined elements from critical theory and a social constructionist perspective guided this study. A qualitative, grounded theory method was used that included semi structured interviews with …

Emergency Department Staff Adherence To Bad News Delivery Recommendations, Kristen R. Myers

Loma Linda University Electronic Theses, Dissertations & Projects

Emergency department (ED) staff is responsible for giving bad news regarding death, diagnoses, and other traumatic losses to patients and loved ones. Individuals receiving traumatic and sudden bad news are at increased risk of serious psychological and physiological consequences of disrupted grief. Despite published recommended practices for providers to help prevent maladaptive grief responses, little research is available on actual bad news delivery practices and factors promoting or hindering adherence to recommendations, and no study specifically explored the ED context.

The study used a qualitative design to explore bad news delivery practices, awareness of recommendations, factors perceived to hinder or …