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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Experiment and bias: the case of parsimony in comparative cognition

Meketa, Irina 22 January 2016 (has links)
Comparative cognition is the interdisciplinary field of animal cognition and behavior studies, which includes comparative psychology and branches of ethology, biology, and neuroscience. My dissertation shows that the quasi-epistemic value of parsimony plays a problematic role in the experimental setting of comparative cognition. More specifically, I argue that an idiosyncratic interpretation of the statistical hypothesis-testing method, known as the Neyman-Pearson Method (NPM), embeds an Occamist parsimony preference into experimental methodology in comparative cognition, which results in an underattribution bias, or a bias in favor of allegedly simple cognitive ontologies. I trace this parsimony preference to the content of the null hypothesis within the NPM, and defend a strategy for modifying the NPM to guard against the underattribution bias. I recommend adopting an evidence-driven strategy for choosing the null hypothesis. Further, I suggest a role for non-empirical values, such as ethical concerns, in the weighting of Type I and Type II error-rates. I contend that statistical models are deeply embedded in experimental practice and are not value-free. These models provide an often overlooked door through which values, both epistemic and non-epistemic, can enter scientific research. Since statistical models generally, and the NPM in particular, play a role in a wide variety of scientific disciplines, this dissertation can also be seen as a case study illustrating the importance of attending to the choice a particular statistical model. This conclusion suggests that various philosophical investigations of scientific practice - from inquiry into the nature of scientific evidence to analysis of the role of values in science - would be greatly enriched by increased attention to experimental methodology, including the choice and interpretation of statistical models.
2

Change Starts With Journal Editors: In Response to Makel (2014)

McBee, Matthew T., Matthews, Michael S. 01 February 2014 (has links)
The editors of the Journal of Advanced Academics comment on Makel (2014). The replicability crisis in psychology is summarized in terms of three focal issues: the "file drawer" problem, lack of replication studies, and the null hypothesis significance testing paradigm. The authors argue that journal editors are uniquely positioned to address all three of these problems via the adoption of new policies for review and publication.
3

A Comprehensive Review of Effect Size Reporting and Interpreting Practices in Academic Journals in Education and Psychology

SUN, SHUYAN 24 September 2008 (has links)
No description available.
4

On determining the power of a test after data collection

Chernoff, William Avram January 1900 (has links)
Master of Science / Department of Statistics / Leigh W. Murray / The term retrospective power describes methods for estimating the true power of a test after data have been collected. These methods have been recommended by some authors when null hypothesis of a test cannot be rejected. This report uses simulations to study power as a construct of an observed effect, variance, sample size, and set level of significance under the balanced one-way analysis of variance model for normally distributed populations with constant variance. Retrospective power, as a construct of sample data, is not recommended when the null hypothesis of a test cannot be rejected. When the p-value of the test is large, estimates for true power tend to fall below the 0.80 level and width-minimized confidence limits for true power tend to be wide.
5

Cétacés et changements environnementaux : Développement et tests d'indicateurs d'état de conservation en vue d'établissement de stratégies de surveillance / Cetaceans and environmental changes : Development and test of conservation status indicators to establish monitoring strategies

Peltier, Hélène 20 December 2011 (has links)
Dans le cadre de nombreuses règlementations, l’établissement de stratégies de suivi des populations de cétacés est devenu un besoin prioritaire. Les principales caractéristiques d’une stratégie de suivi sont la signification écologique, la crédibilité statistique et le rapport qualité/coût élevé. La mise en place d’indicateurs permet de réduire les coûts de suivi, et propose un outil de communication entre scientifiques et gestionnaires. Un indicateur est une donnée vérifiable et mesurable qui renseigne sur plus qu’elle-même. La collecte des données d’échouages est peu coûteuse, mais l’absence de stratégie d’échantillonnage des populations en mer est une entrave à leur utilisation dans le cadre de stratégies de suivi. L’objectif de cette thèse est de développer des indicateurs des populations de cétacés à partir des données d’échouages. Quatre indicateurs ont été développés au cours de cette thèse. La part des cétacés échoués par rapport aux cétacés morts en mer a été estimée. Les séries temporelles d’échouages ont été affranchies des conditions de dérive, par l’établissement de l’hypothèse nulle (hypothèse d’uniformité spatiale et temporelle des cétacés morts en mer) et constitue l’anomalie d’échouage. La cartographie de la mortalité de cétacés a été réalisée, et détermine le nombre de dauphins morts en mer, indépendamment de leur probabilité de s’échouer. Enfin la distribution de mortalité observée par rapport à la distribution attendue des cétacés morts sous l’hypothèse nulle a été calculée. Elle permet d’identifier des zones de fortes mortalité ou abondance relative. Ces quatre indicateurs pourront être intégrés à différents plans de gestion, nationaux ou internationaux. / Under national and international regulations, the establishment of cetacean population monitoring strategies became a priority. Monitoring main expected characteristics are the ecological significance, the statistical credibility and the cost-effectiveness. The use of indicators reduces monitoring cost, and constitutes communication tool between scientists and policy-makers. Indicators are measurable and verifiable data, which inform on more than themselves. The collect of stranding data is cost-efficient, but the lack of sampling strategy remains a hindrance to their use in context of monitoring strategy. The aim of this study is to develop cetacean population indicators based on stranding data.Four indicators were developed during this work. The proportion of stranded cetaceans compared to dead cetaceans at sea was estimated. Stranding long term time series were freed from drift conditions by the construction of the null hypothesis (that is a hypothesis of spatial and temporal uniformity of dead cetaceans). It constituted the stranding anomaly. The cetacean mortality cartography estimated the number of dead cetaceans at sea, independently of the stranding probability. Finally, cetacean mortality anomaly was calculated as the difference between mortality areas of stranded cetaceans and theoretical distribution of dead cetaceans predicted to strand under the null hypothesis. This anomaly identified high mortality or high relative abundance areas. These indicators could be integrated to many national and international management strategies.
6

What’s still wrong with psychology, anyway? Twenty slow years, three old issues, and one new methodology for improving psychological research.

Woods, Bradley Dean January 2011 (has links)
Recent retrospectives of classic psychology articles by Meehl (1978) and Wachtel (1980), concerning problems with psychology’s research paradigm, have been viewed by commentators, on the whole, as germane as when first published. However, no similar examination of Lykken’s (1991) classic criticisms of psychology’s dominant research tradition has been undertaken. Twenty years on, this thesis investigates whether Lykken’s criticisms and conclusions are still valid via an exposition of three contentious issues in psychological science: the measurement problem, null hypothesis significance testing, and the granularity of research methods. Though finding that little progress has been made, Observation Oriented Modelling is advanced as a promising methodological solution for improving psychological research.
7

A scientific analysis of running lines in rugby

Evert, Ashley 13 February 2004 (has links)
The game of rugby has been played for over a century and yet its intricacies are still not fully understood. The key ingredient coaches are seeking is what can be added to a team’s make-up that will result in an increase in that teams level of playing success. The objective of this study is the exploration of the biomechanical aspects of movement in a rugby context specifically looking at the stages before, during and after contact. The hypothesis is that the optimal use of running lines in rugby union will lead to more successful breaches in the opposition’s defensive lines thus an increase in linebreaks will occur. In order to make a comparison based on scientific research principles, nine matches played during the 2001 season was compared with nine matches played during the 2002 season. For each match played in the 2001 and 2002 seasons the total number of linebreaks achieved in a match was calculated. In addition the total number of linebreaks achieved in the 2002 season was further subdivided into the specific categories of intervention in order to determine which intervention had the biggest impact on the total number of linebreaks achieved. By means of video footage of the matches played notational analysis was performed and information was gathered in order to gain data for further evaluation. The actions regarding the execution of the linebreaks were evaluated manually in respect of the intervention that was imposed during the coaching of the team during the 2002 season. Without exception a comparison between similar teams played during both seasons indicated that the total number of linebreaks achieved during the 2002 season was much higher than when the team competed against similar opposition during the 2001 season. The aggregate numbers indicated a significant increase in linebreaks from the 2001 to 2002 season. This conclusion was achieved by means of a simple T-test. Firstly an applied F-test test was done to determine whether the two samples had equal variances or not. Under the null hypothesis we assume that the variances of the two samples are equal, while the alternative states that the two samples have different variances. A value for the test statistic that is greater than the critical value will lead to a rejection of the null hypothesis. The test statistic was calculated and evaluated against the F (8,8) = 2.59 critical value on a 5% level of significance. The value of 15.921 is greater than the critical value of 2.95 and therefore the null hypothesis cannot be accepted, concluding that the two samples do not have equal variances. We then proceeded to test whether the 2002 average linebreaks are significantly higher than the average linebreaks achieved in the 2001 season. Under the null hypothesis the two sample averages are equal. Under the alternative, the 2002 average is higher than the 2001 average. In contrast to normal T-tests this specific test was a one-sided upper or right hand test due to the fact that we are testing whether the one average is greater and not equal to the other. Therefore, we would only reject the null hypothesis of equal sample averages if the test statistic were greater than the appropriate critical value. The calculated test statistic is 4.4827 and was evaluated against the t 0.05,9 = 1.833 critical value. Once again we cannot accept the null hypothesis. Therefore we can conclude that the average of the total linebreaks made during the 2002 season is statistically greater than the average of the total linebreaks made during the 2001 season. The results of this study therefore indicate that the new techniques incorporated into the coaching of the team in 2002 did positively influence the number of linebreaks when compared to the 2001 season. / Dissertation (MA (Human Movement Science))--University of Pretoria, 2005. / Biokinetics, Sport and Leisure Sciences / unrestricted
8

Model for marketing liquefied petroleum gas in Nigeria: Warri as a case study / Nonekuone Jolomi

Nonekuone, Jolomi January 2008 (has links)
Despite the huge national energy resources, many Nigerians do not have access to high quality, modern energy services. For those with access, energy supply lacks reliability, especially in the case of liquefied petroleum gas (LPG). Hence this research considers the possibility of enhancing the household use of LPG. It analyzes the factors affecting the current demand and supply. Salient features of the LPG supply and distribution system were also discussed. On the basis of the existing situation, barriers of increasing LPG use, in particular, the problems regarding affordability, priCing, government poliCies, safety, transportation and distribution were analyzed and identified statistically using the chi-square statistical method as a tool. Finally, on the basis of the challenges identified, suggestions and recommendations were made regarding the policies through which the problems could be overcome. Furthermore, a model was developed and tested for an effective marketing strategy of LPG in Warri Nigeria. ii / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.
9

Model for marketing liquefied petroleum gas in Nigeria: Warri as a case study / Nonekuone Jolomi

Nonekuone, Jolomi January 2008 (has links)
Despite the huge national energy resources, many Nigerians do not have access to high quality, modern energy services. For those with access, energy supply lacks reliability, especially in the case of liquefied petroleum gas (LPG). Hence this research considers the possibility of enhancing the household use of LPG. It analyzes the factors affecting the current demand and supply. Salient features of the LPG supply and distribution system were also discussed. On the basis of the existing situation, barriers of increasing LPG use, in particular, the problems regarding affordability, priCing, government poliCies, safety, transportation and distribution were analyzed and identified statistically using the chi-square statistical method as a tool. Finally, on the basis of the challenges identified, suggestions and recommendations were made regarding the policies through which the problems could be overcome. Furthermore, a model was developed and tested for an effective marketing strategy of LPG in Warri Nigeria. ii / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.
10

New Directions in Quantitative Hispanic Sociolinguistics

January 2015 (has links)
abstract: The present thesis explores how statistical methods are conceptualized, used, and interpreted in quantitative Hispanic sociolinguistics in light of the group of statistical methods espoused by Kline (2013) and named by Cumming (2012) as the “new statistics.” The new statistics, as a conceptual framework, repudiates null hypothesis statistical testing (NHST) and replaces it with the ESCI method, or Effect Sizes and Confidence Intervals, as well as meta-analytic thinking. In this thesis, a descriptive review of 44 studies found in three academic journals over the last decade (2005 – 2015), NHST was found to have a tight grip on most researchers. NHST, much discredited outside of linguistics, confused authors who conflated the theories of Fisher and Neyman-Pearson, who themselves battled acrimoniously until the end of their publishing lives. Within the studies reviewed, with exceptions, dichotomous thinking ruled the quantitative approach, and binary reporting ruled the results and discussions. In addition, this thesis revealed that sociolinguistics, at least within the studies reviewed, is not exactly a “statistical monoculture” as suspected by Gorman and Johnson (2013), rather ANOVAs have joined Goldvarb’s logistic regression in its dominance. As described insightfully by Plonsky (2015), these two methods are exposed as extensions of the dichotomous thinking that attaches itself to NHST. Further, little evidence was found that the methods of the new statistics were being implemented in a coordinated fashion, including far too few meta-analyses. As such, quantitative Hispanic sociolinguistics, and linguistics in general, were shown to be vulnerable to problems with reliable quantitative theory building. / Dissertation/Thesis / Masters Thesis Spanish 2015

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