Global ETD Search

11	Statistical Inference for Generalized Yule Coefficients in 2 × 2 Contingency Tables Bonett, Douglas G., Price, Robert M. 01 February 2007 (has links) The odds ratio is one of the most widely used measures of association for 2 × 2 tables. A generalized Yule coefficient transforms the odds ratio into a correlation-like scale with a range from -1 to 1. Yule's Y, Yule's Q, Digby's H, and a new coefficient are special cases of a generalized Yule coefficient. The new coefficient is shown to be similar in value to the phi coefficient. A confidence interval and sample size formula for a generalized Yule coefficient are proposed. The proposed confidence interval is shown to perform much better than the Wald intervals that are implemented in statistical packages. interval estimation Phi coefficient sample size requirement tetrachoric correlation Mathematics and Statistics
12	Inferential Methods for the Tetrachoric Correlation Coefficient Bonett, Douglas G., Price, Robert M. 01 January 2005 (has links) The tetrachoric correlation describes the linear relation between two continuous variables that have each been measured on a dichotomous scale. The treatment of the point estimate, standard error, interval estimate, and sample size requirement for the tetrachoric correlation is cursory and incomplete in modern psychometric and behavioral statistics texts. A new and simple method of accurately approximating the tetrachoric correlation is introduced. The tetrachoric approximation is then used to derive a simple standard error, confidence interval, and sample size planning formula. The new confidence interval is shown to perform far better than the confidence interval computed by SAS. A method to improve the SAS confidence interval is proposed. All of the new results are computationally simple and are ideally suited for textbook and classroom presentations. interval estimation odds ratio point estimation reliability sample size requirement standard error tetrachoric approximation Mathematics and Statistics
13	Rr Interval Estimation From An Ecg Using A Linear Discrete Kalman Filter Janapala, Arun 01 January 2005 (has links) An electrocardiogram (ECG) is used to monitor the activity of the heart. The human heart beats seventy times on an average per minute. The rate at which a human heart beats can exhibit a periodic variation. This is known as heart rate variability (HRV). Heart rate variability is an important measurement that can predict the survival after a heart attack. Studies have shown that reduced HRV predicts sudden death in patients with Myocardial Infarction (MI). The time interval between each beat is called an RR interval, where the heart rate is given by the reciprocal of the RR interval expressed in beats per minute. For a deeper insight into the dynamics underlying the beat to beat RR variations and for understanding the overall variance in HRV, an accurate method of estimating the RR interval must be obtained. Before an HRV computation can be obtained the quality of the RR interval data obtained must be good and reliable. Most QRS detection algorithms can easily miss a QRS pulse producing unreliable RR interval values. Therefore it is necessary to estimate the RR interval in the presence of missing QRS beats. The approach in this thesis is to apply KALMAN estimation algorithm to the RR interval data calculated from the ECG. The goal is to improve the RR interval values obtained from missed beats of ECG data. Kalman Filter ECG RR Interval Estimation Electrical and Computer Engineering Electrical and Electronics Engineering
14	Löne – och sysselsättningseffekter genererade av återinförandet av ROT-avdraget 2008 : En undersökning av svenska aktiebolag med Difference-in-Difference metod Areflykt, Lucas, Nilsson, Fredrik January 2017 (has links) Syftet med denna undersökning är att analysera eventuella löne- och sysselsättningseffekter generade av återinförandet av ROT-avdraget 2008. Återinförandet sågs som en permanent åtgärd med målet att motverka så kallade svartarbeten och öka byggandet i Sverige. Vi vill med denna undersökning utvärdera vilka löne- och sysselsättningseffekter som ROT-avdraget bidragit till. En difference-in-difference metod kommer att användas för att analysera data insamlade från aktiebolag i Sverige, aggregerat till branschnivå. Aggregeringen görs för att våra resultat skall vara direkt jämförbara med tidigare studier, samt för att inte exkludera den effekt som orsakas av att nya företag i dessa branscher kan ha startats på grund av reformen. Difference-in-difference metoden går ut på att en behandlad grupp bestående av de byggbranscher som påverkats av ROT-avdragets införande jämförs med en kontrollgrupp bestående av övriga branscher före och efter reformen. Våra resultat visar att den genomsnittliga lönesumman per anställd inte påverkats av reformen, medan reformen givit en ökning i det genomsnittliga antalet anställda i ROT-branscherna. / The purpose of this paper is to analyze the possible wage and employment effects generated by the reintroduction of the ROT-deduction in 2008. The reintroduction was seen as a permanent measure, and the aim was to counteract undeclared work and to stimulate and increase the building in Sweden. With this paper, we want to evaluate the wage and employment effects that the ROT-deduction contributed to in Swedish construction companies, more specifically limited companies in the ROT industry. A difference-in-difference method will be used to analyze data collected from limited companies in Sweden, aggregated to industry level. Aggregation is made for our results to be directly comparable to previous studies, and to not exclude the effect caused by new companies in the ROT-industry that may have started due to the reform. The difference-in-difference method involves that a treated group consisting of the construction industries affected by the introduction of the ROT-deduction is compared to a control group consisting of other industries before and after the reform. Our results show that the average wage per employee is not affected by the reform, while the reform has increased the average number of employees in the ROT-industry. ROT-deduction ROT-industry difference-in-difference estimation interval estimation ROT-avdrag ROT-branschen difference-in-difference punktskattning intervallskattning Economics Nationalekonomi
15	Adjusted Wald Confidence Interval for a Difference of Binomial Proportions Based on Paired Data Bonett, Douglas G., Price, Robert M. 01 August 2012 (has links) Adjusted Wald intervals for binomial proportions in one-sample and two-sample designs have been shown to perform about as well as the best available methods. The adjusted Wald intervals are easy to compute and have been incorporated into introductory statistics courses. An adjusted Wald interval for paired binomial proportions is proposed here and is shown to perform as well as the best available methods. A sample size planning formula is presented that should be useful in an introductory statistics course. binomial distribution interval estimation Laplace estimate matched-pairs repeated measures sample size score interval within-subjects design Mathematics and Statistics
16	Agency of others : The intentional binding paradigm in observed actions Hallberg, Erik, Lundstedt, Ludwig January 2023 (has links) Sense of agency (SoA) is defined as the subjective experience of being in control of our own actions. This attribution of control underpins all human action and is a vital aspect of the experience of being human. This systematic review sought to address whether intentional binding (IB), a proxy of SoA, can be found during observation of other-generated actions. This was done by investigating the current state of research in the field. Past studies are inconclusive in regards to what factors play into the formation of SoA and the motivation behind this review was to provide a conclusion regarding IB from observed actions. The studies featured in this review found that the IB effect was present in different procedures and contexts which highlights the flexible nature of SoA. Most importantly, this systematic review concluded that IB can and does occur during the observation of other-generated actions. Furthermore, this review found that social influence has an effect on SoA in both human- and robot-observations. We also found that the IB effect manifests in the absence of voluntary actions but to a lesser degree. However, the magnitude of the IB effect varied across studies where one found IB to be greater during action observation than self-generated actions, whilst another study found a weaker IB effect for action observation. Finally, this review provides a discussion on theories that best explain this phenomena, the neural evidence behind action observation, and what implications the findings could have for SoA as a whole sense of agency intentional binding action observation intentional binding paradigm interval estimation paradigm Neurosciences Neurovetenskaper Environmental Sciences Miljövetenskap
17	Statistická analýza ROC křivek / Statistical analysis of ROC curves Kutálek, David January 2010 (has links) The ROC (Receiver Operating Characteristic) curve is a projection of two different cumulative distribution functions F0 and F1. On axis are values 1-F0(c) and 1-F1(c). The c-parameter is a real number. This curve is useful to check quality of discriminant rule which classify an object to one of two classes. The criterion is a size of an area under the curve. To solve real problems we use point and interval estimation of ROC curves and statistical hypothesis tests about ROC curves.
18	Confidence Intervals for a Ratio of Binomial Proportions Based on Paired Data Bonett, Douglas, Price, Robert M. 15 September 2006 (has links) Four interval estimation methods for the ratio of marginal binomial proportions are compared in terms of expected interval width and exact coverage probability. Two new methods are proposed that are based on combining two Wilson score intervals. The new methods are easy to compute and perform as well or better than the method recently proposed by Nam and Blackwelder. Two sample size formulas are proposed to approximate the sample size required to achieve an interval estimate with desired confidence level and width. continuity correction cross-over design interval estimation matched-pairs design repeated measures design sample size score interval wald interval wilson interval Mathematics and Statistics
19	Apport de la résonance magnétique nucléaire des solides à la caractérisation chimique et à la datation des os en anthropologie médico-légale / The contribution of solid-state nuclear magnetic resonance to the chemical characterization and to the bone datation in forensic anthropology Urzel, Vanessa 19 March 2014 (has links) L’estimation du délai post mortem est une étape fondamentale en anthropologie médico-légale. À ce jour, peu de méthodes précises et fiables existent. Les objectifs de notre travail étaient d’étudier le tissu osseux et son évolution dans les années et siècles suivant le décès en développant la Résonance Magnétique Nucléaire (RMN) des solides du carbone13C et du proton1H. Nous avons analysé une centaine d’os humains et animaux pour lesquels nous connaissions l’âge au décès, le sexe, la date de décès et les conditions de conservation. Nous avons caractérisé les os au niveau moléculaire en identifiant le collagène, les lipides et l’hydroxyapatite constitutifs du tissu osseux. Nous avons développé une méthode RMN permettant de distinguer des altérations de certains échantillons attestant de la présence d’adipocire au sein du tissu osseux, ou des dégradations sur des échantillons très anciens. L’étude de l’âge au décès et du sexe des sujets n’a pas mis en évidence une grande influence de ces facteurs sur les données RMN même si, pour des délais post mortem de 0 ou 1 an, les sujets féminins présentent quantitativement plus de lipides que les sujets masculins. L’analyse des conditions de conservation des individus montre un développement plus important d’adipocire pour les os laissés à l’air libre comparés aux os enterrés. Enfin, nous rapportons une décroissance quantitative du collagène et des lipides présents au sein du tissu osseux lorsque l’intervalle post mortem augmente. Cette décroissance est beaucoup plus rapide pour les lipides (quelques années) que pour le collagène (plusieurs millénaires) alors que l’hydroxyapatite présente une relative stabilité dans les premiers siècles suivant le décès. / The post mortem interval estimation is a fundamental step in forensic anthropology and up to now there are little accurate and reliable methods to do so. The objectives of our study were to investigate the bone composition and its evolution over years and centuries following the death by developing carbon 13C and proton 1H solid-state nuclear magnetic resonance (NMR). We analyzed about one hundred human and animal bones for which the age at death, sex, date of death and the storage conditions were known. Bones were characterized at the molecular level by identification of collagen, lipids and hydroxyapatite embedded in the bone matrix. We have designed a NMR-based method that allows determining alterations on some samples, evidencing the presence of adipocere (bone wax) within the bone, or finding bone tissue deterioration on some very old samples. Subject age at death and sex did not reveal significant changes on NMR data, except for post mortem interval ranging between 0 to 1 year, where female subjects had quantitatively more lipids in their bones than males. Storage conditions may promote a greater development of adipocere especially for bones left in the open air compared to those buried. Finally, we report a quantitative decrease of collagen and lipids present in the bone tissue when the post mortem interval increases. This decrease is much faster for lipids than for collagen where as the hydroxyapatite has a relative stability in the first centuries after the death. Decreases occur with very different time constants, ranging from years to millennia. Anthropologie médico-légale Estimation de l’intervalle post mortem Os Collagène de type I Lipides Hydroxyapatite Forensic anthropology Solid-state Nuclear Magnetic Resonance, Post mortem interval estimation Bones Type 1 collagen Lipids Hydroxyapatite
20	Statistical Inference Chou, Pei-Hsin 26 June 2008 (has links) In this paper, we will investigate the important properties of three major parts of statistical inference: point estimation, interval estimation and hypothesis testing. For point estimation, we consider the two methods of finding estimators: moment estimators and maximum likelihood estimators, and three methods of evaluating estimators: mean squared error, best unbiased estimators and sufficiency and unbiasedness. For interval estimation, we consider the the general confidence interval, confidence interval in one sample, confidence interval in two samples, sample sizes and finite population correction factors. In hypothesis testing, we consider the theory of testing of hypotheses, testing in one sample, testing in two samples, and the three methods of finding tests: uniformly most powerful test, likelihood ratio test and goodness of fit test. Many examples are used to illustrate their applications. finite population correction factor statistical hypothesis type I error composite hypothesis power Central limit theorem Basu theorem critical value goodness of fit test likelihood ratio test Lehmann-Scheffe theorem complete statistic ancillary statistic P-value type II error Rao-Blackwell theorem simple hypothesis one-sided test two-sided test significance level sufficient statistic alternative hypothesis testing hypothesis null hypothesis rejection region confidence interval confidence level minimum variance unbiased estimator interval estimation uniformly most powerful test Cramer-Rao inequality likelihood function mean square error moment estimator error of estimation point estimation maximum likelihood estimator bias consistent estimator minimal sufficient statistic factorization theorem unbiased estimator statistic most powerful test test statistics Neyman-Pearson lemma decision rule

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