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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

Three essays on hypotheses testing involving inequality constraints

Hsu, Yu-Chin, 1978- 21 September 2010 (has links)
The focus of this research is on hypotheses testing involving inequality constraints. In the first chapter of this dissertation, we propose Kolmogorov-Smirnov type tests for stochastic dominance relations between the potential outcomes of a binary treatment under the unconfoundedness assumption. Our stochastic dominance tests compare every point of the cumulative distribution functions (CDF), so they can fully utilize all information in the distributions. For first order stochastic dominance, the test statistic is defined as the supremum of the difference of two inverse-probability-weighting estimators for the CDFs of the potential outcomes. The critical values are approximated based on a simulation method. We show that our test has good size properties and is consistent in the sense that it can detect any violation of the null hypothesis asymptotically. First order stochastic dominance tests in the treated subpopulation, and higher order stochastic dominance tests in the whole population and among the treated are shown to share the same properties. The tests are applied to evaluate the effect of a job training program on incomes, and we find that job training has a positive effect on real earnings. Finally, we extend our tests to cases in which the unconfoundedness assumption does not hold. On the other hand, there has been a considerable amount of attention paid to testing inequality restrictions using Wald type tests. As noted by Wolak (1991), there are certain situations where it is difficult to obtain tests with correct size even asymptotically. These situations occur when the variance-covariance matrix of the functions in the constraints depends on the unknown parameters as would be the case in nonlinear models. This dependence on the unknown parameters makes it computationally difficult to find the least favorable configuration (LFC) which can be used to bound the size of the test. In the second chapter of this dissertation, we extend Hansen's (2005) superior predictive ability (SPA) test to testing hypotheses involving general inequality constraints in which the variance-covariance matrix can be dependent on the unknown parameters. For our test we are able to obtain correct size asymptotically plus test consistency without requiring knowledge of the LFC. Also the test can be applied to a wider class of problems than considered in Wolak (1991). In the last chapter, we construct new Kolmogorov-Smirnov tests for stochastic dominance of any pre-specified order without resorting to the LFC to improve the power of Barrett and Donald's (2003) tests. To do this, we first show that under the null hypothesis if the objects being compared at a given income level are not equal, then the objects at this given income level will have no effect on the null distribution. Second, we extend Hansen's (2005) recentering method to a continuum of inequality constraints and construct a recentering function that will converge to the underlying parameter function uniformly asymptotically under the null hypothesis. We treat the recentering function as a true underlying parameter function and add it to the simulated Brownian bridge processes to simulate the critical values. We show that our tests can control the size asymptotically and are consistent. We also show that by avoiding the LFC, our tests are less conservative and more powerful than Barrett and Donald's (2003). Monte Carlo simulations support our results. We also examine the performances of our tests in an empirical example. / text
2

Exponenciální třídy a jejich význam pro statistickou inferenci / Exponenciální třídy a jejich význam pro statistickou inferenci

Moneer Borham Abdel-Maksoud, Sally January 2011 (has links)
This diploma thesis provides an evaluation of Exponential families of distributions which has a special position in mathematical statistics. Diploma will learn the basic concepts and facts associated with the distribution of exponential type. Especially with focusing on the advantages of exponential families in classical parametric statistics, thus in theory of estimation and hypothesis testing. Emphasis will be placed on one-parameter and multi-parameters systems.
3

Exponenciální třídy a jejich význam pro statistickou inferenci / Exponenciální třídy a jejich význam pro statistickou inferenci

Moneer Borham Abdel-Maksoud, Sally January 2011 (has links)
Title: Exponential families in statistical inference Author: Sally Abdel-Maksoud Department: Department of Probability and Mathematical Statistics Supervisor: doc. RNDr. Daniel Hlubinka, Ph.D. Supervisor's e-mail address: Daniel.Hlubinka@mff.cuni.cz Abstract: This diploma thesis provides an evaluation of Exponential families of distributions which has a special position in mathematical statistic including appropriate properties for estimation of population parameters, hypothesis testing and other inference problems. Diploma will introduce the basic concepts and facts associated with the distribution of exponential type especially with focusing on the advantages of exponential families in classical parametric statistics, thus in theory of estimation and hypothesis testing. Emphasis will be placed on one-parameter and multi- parameters systems. It also exposes an important concepts about the curvature of a statistical problem including the curvature in exponential families. We will define a quantity that measure how nearly "exponential" the families are. This quantity is said to be the statistical curvature of the family. We will show that the family with a small curvature enjoy the good properties of exponential families Moreover, the properties of the curvature, hypotheses testing and some...
4

Propriedades lógicas de classes de testes de hipóteses / Logical properties of classes of hypotheses tests

Silva, Gustavo Miranda da 03 November 2014 (has links)
Ao realizar testes de hipóteses simultâneos espera-se que a decisões obtidas neles sejam logicamente consistentes entre si. Neste trabalho, verifica-se sob quais condições testes de Bayes simultâneos atendem às condições lógicas isoladamente ou em conjunto. Demonstra-se que as restrições para que os testes simultâneos atendam essas condições isoladamente são bastante intuitivas. No entanto, ao tentar obedecer as condições conjuntamente, perde-se otimalidade. Além disso, avalia-se a relação entre esses testes de Bayes simultâneos e os testes gerados por estimadores, isto é, mostra-se que, sob algumas condições, tomar uma decisão baseado em um estimador de Bayes é equivalente a tomar uma decisão baseada em um teste de Bayes. Por fim, mostra-se que, se tomamos uma decisão baseada em Estimadores de Máxima Verossimilhança, então essa decisão deve ser igual à tomada por um teste de Bayes e concluímos que essas decisões são admissíveis e obedecem ao Princípio da Verossimilhança. / When performing simultaneous hypotheses testing is expected that the decisions obtained therein are logically consistent with each other. In this work, we find restrictions under which simultaneous Bayes tests meet logical conditions separately or jointly. It is shown that the conditions for the simultaneous tests meet these conditions alone are quite intuitive. However, when trying to obey the conditions jointly, we lose optimality. Furthermore, we evaluate the relationship between these tests and simultaneous Bayes tests generated by estimators, ie, we show that, under some conditions, to choose an estimator based on Bayes decision is equivalent to choosing a decision based on a Bayes test. Finally, we show that if we take a decision based on Maximum Likelihood Estimators, then that decision should be equal to taking a Bayes test and concluded that these decisions are admissible and obey the Likelihood Principle.
5

Stabilita v autoregresních modelech časových řad / Stability in Autoregressive Time Series Models

Dvořák, Marek January 2015 (has links)
The main subject of this thesis is a change point detection in stationary vector autoregressions. Various test statistics are proposed for the retrospective break point detection in the parameters of such models, in particular, the derivation of their asymptotic distribution under the null hypothesis of no change. Testing procedures are based on the maximum like- lihood principle and are derived under normality, nevertheless the asymptotic results are valid for broader class of distributions and involve also the models with certain form of dependence. Simulation studies document the quality of the results.
6

Propriedades lógicas de classes de testes de hipóteses / Logical properties of classes of hypotheses tests

Gustavo Miranda da Silva 03 November 2014 (has links)
Ao realizar testes de hipóteses simultâneos espera-se que a decisões obtidas neles sejam logicamente consistentes entre si. Neste trabalho, verifica-se sob quais condições testes de Bayes simultâneos atendem às condições lógicas isoladamente ou em conjunto. Demonstra-se que as restrições para que os testes simultâneos atendam essas condições isoladamente são bastante intuitivas. No entanto, ao tentar obedecer as condições conjuntamente, perde-se otimalidade. Além disso, avalia-se a relação entre esses testes de Bayes simultâneos e os testes gerados por estimadores, isto é, mostra-se que, sob algumas condições, tomar uma decisão baseado em um estimador de Bayes é equivalente a tomar uma decisão baseada em um teste de Bayes. Por fim, mostra-se que, se tomamos uma decisão baseada em Estimadores de Máxima Verossimilhança, então essa decisão deve ser igual à tomada por um teste de Bayes e concluímos que essas decisões são admissíveis e obedecem ao Princípio da Verossimilhança. / When performing simultaneous hypotheses testing is expected that the decisions obtained therein are logically consistent with each other. In this work, we find restrictions under which simultaneous Bayes tests meet logical conditions separately or jointly. It is shown that the conditions for the simultaneous tests meet these conditions alone are quite intuitive. However, when trying to obey the conditions jointly, we lose optimality. Furthermore, we evaluate the relationship between these tests and simultaneous Bayes tests generated by estimators, ie, we show that, under some conditions, to choose an estimator based on Bayes decision is equivalent to choosing a decision based on a Bayes test. Finally, we show that if we take a decision based on Maximum Likelihood Estimators, then that decision should be equal to taking a Bayes test and concluded that these decisions are admissible and obey the Likelihood Principle.
7

Testování ekvivalence a noninferiority / Testing equivalence and noninferiority

Rychterová, Nela January 2019 (has links)
This master thesis deals with topics related to the task whether customers are able to recognize a difference between products. First, testing of equivalence and non-inferiority is discussed in detail. It is an important tool when verifying that two products are equivalent or that a new product is not substantially worse than a current product. Afterwards, Thurstone's approach is introduced as a way to evaluate the impact of a stimulus on human senses. Subsequently, using the previous chapters, there is a detailed discussion dealing with three standards wi- dely used in practice in the case when someone needs to apply sensory evaluation to verify whether customers are able to recognize a difference between products. In particular, these are duo-trio, triangle and paired comparison tests. There is a thorough explanation of their statistical base and the tests are compared accor- ding to their power. Furthermore, an approach based on the Thurstone's theory is introduced as an alternative to the standard methods. Moreover, this thesis introduces Saaty's approach to the estimation of a priority vector, which is a useful tool to compare, to order or to choose the best one from n objects. We also introduce another approach to estimation of a priority vector which is based on Saaty's idea. 1
8

Post Alarm Analysis using Active Connection

Vodela, Vindhya 14 October 2013 (has links)
No description available.
9

Bayesian Hidden Markov Model in Multiple Testing on Dependent Count Data

Su, Weizhe January 2020 (has links)
No description available.
10

Frivillig miljökompensation : Klädkonsumentens vilja att täcka plaggets fulla kostnad / Voluntary Environmental Offset for Clothing

Johansson Tapper, Erik, Svensson, Sofia January 2017 (has links)
Det är känt att modeindustrin har ett stort anspråk på miljön, men trots det finns det inga fungerande lösningar på problemet i dagsläget. Ett sätt att komma till bukt med problemet äratt låta konsumenten miljökompensera vid köptillfället. Den här studien undersöker konsumenters inställning till en frivillig miljökompensation vid klädköp. Liknande studier har gjorts tidigare, då på flygresenärers vilja att frivilligt klimatkompensera för koldioxidutsläpp. Det har därför varit av intresse att testa liknande undersökningsmetod på konsumenter imodeindustrin. Tidigare forskning har konstaterat att ett flertal variabler är betydande för konsumentens vilja göra grönare konsumtionsval. Detta har mynnat ut i fyra hypoteser som testar hur konsumenters attityd till miljökompensation, upplevda konsumenteffektivitet, upplevda miljökunskap samt kön korrelerar med viljan att miljökompensera. Studien har även undersökt hur konsumenternas vilja att kompensera påverkar det ekonomiska värdet som konsumenten sätter på miljöproblemen kopplade till klädproduktion. Undersökningen bygger på 225 enkätsvar från studenter vid en medelstor svensk högskola. Resultaten från studien visar på signifikanta samband mellan flera av de förklarande variablerna och viljan att delta i frivillig miljökompensation. Den genomsnittliga kompensationsnivån uppgår till halva plaggets försäljningspris, vilket är en uppseendeväckande siffra. Respondenternas preferenser visar även att miljökompensationen bör fördelas lika över olika projekt för bättre miljö. / Although it’s known what footprint the global fashion industry has, few solutions have effectively managed to tackle the problem. One solution is to let the consumer participate in avoluntary environmental offset. This study investigates what variables affecting the consumer’s willingness to participate in such offset. Similar studies on air travelers’ voluntarycarbon offset have been done before. It’s therefore of interest to use the same preference method on consumers of the fashion industry. Previous research present a number of independent variables affecting the willingness to participate in voluntary offset. This study uses four hypotheses to explain consumers’ stated preferences. These include attitudes, perceived consumer effectiveness, perceived ecoliteracy and gender. The study uses a contingent valuation method to explain how the willingness to participate correlates with the hypothetical value of the voluntary environmental offset. An online survey was conducted and included data of 225 respondents. The results show significant correlations among several of the independent variables and the willingness to participate in voluntary environmental offset. The average value of offset reached about half the selling price of a simulated garment, which is staggering. The respondents’ preferences on how the money from the offset should be allocated tell of an equal share among projects for a better environment. The study is a bachelor thesis written in Swedish.

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