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Description
Quadratic growth curves of 2nd degree polynomial are widely used in longitudinal studies. For a 2nd degree polynomial, the vertex represents the location of the curve in the XY plane. For a quadratic growth curve, we propose an approximate confidence region as well as the confidence interval for x and y-coordinates of the vertex using two methods, the gradient method and the delta method. Under some models, an indirect test on the location of the curve can be based on the intercept and slope parameters, but in other models, a direct test on the vertex is required. We present a quadratic-form statistic for a test of the null hypothesis that there is no shift in the location of the vertex in a linear mixed model. The statistic has an asymptotic chi-squared distribution. For 2nd degree polynomials of two independent samples, we present an approximate confidence region for the difference of vertices of two quadratic growth curves using the modified gradient method and delta method. Another chi-square test statistic is derived for a direct test on the vertex and is compared to an F test statistic for the indirect test. Power functions are derived for both the indirect F test and the direct chi-square test. We calculate the theoretical power and present a simulation study to investigate the power of the tests. We also present a simulation study to assess the influence of sample size, measurement occasions and nature of the random effects. The test statistics will be applied to the Tell Efficacy longitudinal study, in which sound identification scores and language protocol scores for children are modeled as quadratic growth curves for two independent groups, TELL and control curriculum. The interpretation of shift in the location of the vertices is also presented.
ContributorsYu, Wanchunzi (Author) / Reiser, Mark R. (Thesis advisor) / Barber, Jarrett (Committee member) / Kao, Ming-Hung (Committee member) / St Louis, Robert D (Committee member) / Wilson, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2015
Description
We attempted to apply a novel approach to stock market predictions. The Logistic Regression machine learning algorithm (Joseph Berkson) was applied to analyze news article headlines as represented by a bag-of-words (tri-gram and single-gram) representation in an attempt to predict the trends of stock prices based on the Dow Jones Industrial Average. The results showed that a tri-gram bag led to a 49% trend accuracy, a 1% increase when compared to the single-gram representation’s accuracy of 48%.
ContributorsBarolli, Adeiron (Author) / Jimenez Arista, Laura (Thesis director) / Wilson, Jeffrey (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Psychedelics have sparked widespread interest as they offer a potential new form of therapeutic treatment. This thesis paper explores the current and upcoming psychedelics that are being researched for their use in a therapeutic setting. The main substances discussed are lysergic acid diethylamide (LSD), methylenedioxymethamphetamine (ecstasy/molly/MDMA), and ketamine (esketamine). This paper also discusses the mechanism of action for each drug and the underlying research that has been found to support the ethical use of these substances alongside talk therapy
ContributorsPiemont, Sabrina (Author) / Jimenez Arista, Laura (Thesis director) / Ocampo Hoogasian, Rachel (Committee member) / Barrett, The Honors College (Contributor) / College of Integrative Sciences and Arts (Contributor)
Created2023-05
Description
Research in intercollegiate athletics has provided a relatively large body of findings about the kinds of stressors found in high profile intercollegiate athletic environments and their effects on student-athletes. Research is less robust regarding stress and its effects on head coaches in high profile collegiate athletics. This study focuses on the types, frequencies, and intensities of stress experienced by NCAA, Division I head coaches. The purpose of the study is to identify the types, frequency, and intensity of stress common to 20 head basketball coaches participating in the study, as well as differences in their experiences based on gender, race and the intersectionality of race and gender. The participants in the study are 20 head coaches (five Black females, five Black males, five White females, and White males). The conceptual framework guiding the study is a definition of stress as an interaction between a person and her or his environment in which the person perceives the resources available to manage the situation to be inadequate (Lazarus & Folkman, 1984). The study’s design is an adaptation of prior research conducted by Frey, M., 2007 and Olusoga, P., Butt, J., Hays, K., & Maynard, I., 2009, and Olusoga, P., Butt, J., Maynard, I., & Hays, K., 2011. This study used qualitative and quantitative methods that triangulated results scores on Maslach’s Burn-out Inventory and the Perceived Stress Scale with the thick data collected from semi-structured interviews with the 20 head coaches from each of the three data sources to enhance the validity and reliability of the findings. The researcher analyzed the data collected by placing it in one of two categories, one representing attributes of the participants including race and gender; the second category was comprised of attributes of the Division I environment.
ContributorsRousseau, Julie B (Author) / Gray, Rob (Thesis advisor) / Vega, Sujey (Committee member) / Wilson, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2019