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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.
341

Nonparametric Tests for Umbrella Alternatives in Stratified Datasets

Larock, Josh 15 August 2023 (has links)
This thesis considers the problem of hypothesis testing for umbrella alternatives when there are two groups, or strata, of observations. The proposed methods extend a previously established general framework of hypothesis testing based on rankings to stratified datasets by first aligning the strata. The tests based on the Spearman and Kendall distances between ranking vectors lead to the traditional aligned-rank tests and new methods which account for “misalignment” under the alternative hypothesis. Asymptotic null distributions and simulation studies are given for the Spearman distance. Diagnostic tools for the misalignment issue are illustrated alongside the proposed tests on a dataset of IQ scores of coma patients. Extensions to three or more strata and ”adaptive” tests are provided as future research directions.
342

Three essays on econometrics / 計量経済学に関する三つの論文

Yi, Kun 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(経済学) / 甲第24375号 / 経博第662号 / 新制||経||302(附属図書館) / 京都大学大学院経済学研究科経済学専攻 / (主査)教授 西山 慶彦, 教授 江上 雅彦, 講師 柳 貴英 / 学位規則第4条第1項該当 / Doctor of Economics / Kyoto University / DFAM
343

Semiparametric Bayesian Joint Modeling with Applications in Toxicological Risk Assessment

Hwang, Beom Seuk 06 August 2013 (has links)
No description available.
344

Principal Components Analysis, Factor Analysis and Trend Correlations of Twenty-Eight Years of Water Quality Data of Deer Creek Reservoir, Utah

Gonzalez, Nicolas Alejandro 02 July 2012 (has links) (PDF)
I evaluated twenty-eight years (1980-2007) of spatial-temporal water quality data from Deer Creek Reservoir in Utah. The data came from three sampling points representing the lotic, transitional and lentic zones. The data included measurements of climatological, hydrological and water quality conditions at four depths; Surface, Above Thermocline, Below Thermocline and Bottom. The time frame spanned dates before and after the completion of the Jordanelle Reservoir (1987-1992), approximately fourteen miles upstream of Deer Creek. I compared temporal groupings and found that a traditional month distribution following standard seasons was not effective in characterizing the measured conditions; I developed a more representative seasonal grouping by performing a Tukey-Kramer multiple comparisons adjustment and a Bonferronian correction of the Student's t comparison. Based on these analyses, I determined the best groupings were Cold (December - April), Semi-Cold (May and November), Semi-Warm (June and October), Warm (July and September) and Transition (August). I performed principal component analysis (PCA) and factor analysis (FA) to determine principal parameters associated with the variability of the water quality of the reservoir. These parameters confirmed our seasonal groups showing the Cold, Transition and Warm seasons as distinct groups. The PCA and FA showed that the variables that drive most of the variability in the reservoir are specific conductivity and variables related with temperature. The PCA and FA showed that the reservoir is highly variable. The first 3 principal components and rotated factors explained a cumulative 59% and 47%, respectively of the variability in Deer Creek. Both parametric and nonparametric approaches provided similar correlations but the evaluations that included censored data (nutrients) were considerably different with the nonparametric approach being preferred.
345

Energy-Statistics-Based Nonparametric Tests for Change Point Analysis

Njuki, Joseph Mwendwa 23 August 2022 (has links)
No description available.
346

An Assessment of The Nonparametric Approach for Evaluating The Fit of Item Response Models

Liang, Tie 01 February 2010 (has links)
As item response theory (IRT) has developed and is widely applied, investigating the fit of a parametric model becomes an important part of the measurement process when implementing IRT. The usefulness and successes of IRT applications rely heavily on the extent to which the model reflects the data, so it is necessary to evaluate model-data fit by gathering sufficient evidence before any model application. There is a lack of promising solutions on the detection of model misfit in IRT. In addition, commonly used fit statistics are not satisfactory in that they often do not possess desirable statistical properties and lack a means of examining the magnitude of misfit (e.g., via graphical inspections). In this dissertation, a newly-proposed nonparametric approach, RISE was thoroughly and comprehensively studied. Specifically, the purposes of this study are to (a) examine the promising fit procedure, RISE, (b) compare the statistical properties of RISE with that of the commonly used goodness-of-fit procedures, and (c) investigate how RISE may be used to examine the consequences of model misfit. To reach the above-mentioned goals, both a simulation study and empirical study were conducted. In the simulation study, four factors including ability distribution, sample size, test length and model were varied as the factors which may influence the performance of a fit statistic. The results demonstrated that RISE outperformed G2 and S-X2 in that it controlled Type I error rates and provided adequate power under all conditions. In the empirical study, the three fit statistics were applied to one empirical data and the misfitting items were flagged. RISE and S-X2 detected reasonable numbers of misfitting items while G2 detected almost all items when sample size is large. To further demonstrate an advantage of RISE, the residual plot on each misfitting item was shown. Compared to G2 and S-X2, RISE gave a much clearer picture of the location and magnitude of misfit for each misfitting item. Other than statistical properties and graphical displays, the score distribution and test characteristic curve (TCC) were investigated as model misfit consequence. The results indicated that for the given data, there was no practical consequence on classification before and after replacement of misfitting items detected by three fit statistics.
347

Measuring bivariate asymmetry and testing bivariate symmetry

Riahi, Sheida 07 August 2020 (has links)
The present work generalizes the necessary condition of univariate symmetry of Patil et al. (2012) to the bivariate setting, develops a test of bivariate symmetry based on it, and generalizes the measure of asymmetry in Patil et al. (2014) to the bivariate setting. In doing so, as a byproduct, it pays attention to the interrelation between central symmetry and symmetry about an axis of a continuous bivariate density function.
348

Econometric Analysis of Firm-level Production Data

Kealey, John 11 1900 (has links)
In this dissertation, I explore a variety of methods for the econometric analysis of firm-level production data. Three distinct approaches are considered, namely i) proxy variable methods of controlling for unobservable productivity, ii) data envelopment techniques for estimating the boundary of a production set, and iii) stochastic frontier methods for estimating the productive inefficiency of firms. Much of the focus is on semiparametric and nonparametric estimators that allow for a highly flexible specification of the function that relates input combinations to output quantities. / Thesis / Doctor of Philosophy (PhD)
349

Transformations and Bayesian Estimation of Skewed and Heavy-Tailed Densities

Bean, Andrew Taylor January 2017 (has links)
No description available.
350

Two Essays on Single-index Models

Wu, Zhou 24 September 2008 (has links)
No description available.

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