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The purpose of this work is to discover an optimum sample size to be used for deciding between two methods (populations) to choose for future production. The procedure involves the formulation of a loss function, expressing the expected loss due to choosing the population with the small mean, as a function of the difference between the population means, the amount to be produced and the cost of sampling. A minimax procedure is applied to obtain the optimum sample size. Since the function does not lend itself conveniently to mathematical considerations, special cases involving the difference between the means are considered and an optimum sample size is found for these cases. In all cases, the optimum sample size is an explicit function of the amount to be produced, the cost of sampling and the standard deviation. / Master of Science

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Since its issuance in June 1981, Statement on Auditing Standards (SAS) No. 39, "Audit Sampling," has been the center of much controversy. Practitioners are voicing their concerns as they anticipate difficulties in designing, selecting, and evaluating a nonstatistical sampling procedure in accordance with SAS 39. This proposed exploratory study seeks to identify those factors that underlie the auditor's judgment with respect to nonstatistical sample size decisions in substantive tests. The research will utilize Egon Brunswik's Lens Model to provide mathematical representations of the auditor's judgment process. Correlational statistics will be used to assess judgment accuracy, agreement (consensus) , and auditor "self-insight" into his decision process. The study will provide empirical insight, into whether the auditor's determination of the appropriate extent of testing is consistent with his judgment as to the assurance level needed from his sampling application, or conversely, the degree of risk he is willing to accept. The ability of auditors to formulate their sample size decisions properly is crucial because of their impact on audit effectiveness and efficiency. In addition, this project should provide additional evidence bearing upon the arguments of both proponents and opponents of SAS 39. / Ph. D.

Benzene, toluene, ethylbenzene, and xylenes (BTEX) are hazardous air pollutants commonly found in outdoor air. Several studies have explored the potential of vegetation to mitigate BTEX in outdoor air, but they are limited to a northern temperate climate and present conflicting results. To investigate this issue in a subtropical climate, we deployed passive air samplers for two weeks in parks and nearby residences at four locations: three in an urban area and one in a rural area in Alabama, USA. All BTEX concentrations were below health-based guidelines and were comparable to those found in several other studies in populated settings. Concentrations of TEX, but not benzene, were 3-39% lower in parks than at nearby residences, and the differences were significant. In and around two of the parks, toluene:benzene ratios fell outside the range expected for vehicular emissions (p<0.01), suggesting that there are additional, industrial sources of benzene near these two locations. The ratio of m-,p-xylene:ethylbenzene was high at all locations except one residential area, indicating that BTEX were freshly emitted. Concentrations of individual BTEX compounds were highly correlated with each other in most cases, except for locations that may be impacted by nearby industrial sources of benzene. Results of this study suggest that parks can help reduce BTEX exposure by a modest amount, but future research is needed to ascertain this potential through more measurements at higher spatial and temporal resolution and analysis of vegetation for evidence of uptake of BTEX. / Master of Science / Benzene, toluene, ethylbenzene, and xylenes (BTEX) compose a significant fraction of anthropogenic non-methane organic gases in the atmosphere. These compounds are harmful to human health and are precursors to secondary organic aerosol and ozone. Several chamber studies have demonstrated that plants can reduce exposure to BTEX in indoor environments, but, to the best of our knowledge, no study has identified this effect in ambient air. To investigate this issue, we sampled for two weeks in parks and nearby residences at four locations; three were in the city of Birmingham, Alabama, and one was in the rural city of Camden, Alabama. All BTEX concentrations were below health-based guidelines and were comparable to those found in several other studies in urban and rural settings. TEX levels were lower in parks compared to residential areas, and the difference was significant. BTEX were attributable to vehicular emissions in the Camden site and one Birmingham site. In the other two Birmingham sites, there were likely additional, industrial sources of benzene. Future research should investigate the effect of different types of vegetation between parks and explore seasonal cycles in vegetation.

This thesis explores an approach to predicting recidivism by leveraging crowdsourcing, contrasting traditional judicial discretion and algorithmic models. Instead of relying on judges or algorithms, participants predicted the likelihood of re-offending using the COMPAS dataset, which includes demographic and criminal record information. The study analyzed both quantitative and qualitative data to assess biases in human versus algorithmic predictions. Findings reveal that homogeneous crowds reflect the biases of their composition, leading to more pronounced gender and racial biases. In contrast, heterogeneous crowds, with equal and random distributions, present a more balanced view, though underlying biases still emerge. Both gender and racial biases influence how re-offending risk is perceived, significantly impacting risk evaluations. Specifically, crowds rated African American offenders as less likely to re-offend compared to COMPAS, which assigned them higher risk scores, while Caucasian and Hispanic offenders were perceived as more likely to re-offend by crowds. Gender differences also emerged, with males rated as less likely to re-offend and females as more likely. This study highlights crowdsourcing's potential to mitigate biases and provides insights into balancing consistency and fairness in risk assessments. / Master of Science / Within the criminal justice system, predicting whether someone will re-offend has typically depended on the judgment of judges and computerized systems. This thesis investigates another avenue for predicting re-offending by using crowdsourcing, which gathers input from a group of people. In this study, participants were asked to predict the likelihood of re-offending for several offenders using demographic and criminal record information from the publicly available COMPAS dataset. Participants provided scores, and some also explained their reasoning. Bias, defined as a systematic unfairness that leads to prejudiced outcomes, was a key focus. To understand bias, the study created different groups within the participant crowd based on age, gender, and race, and compared their predictions with COMPAS scores. The analysis revealed important insights into the biases present in both human and algorithmic predictions. A homogeneous crowd, is associated with minimal differences in ratings across genders and races, suggesting a consistent but potentially biased perspective. While a diverse crowd, leads to varied ratings without a clear trend, reflecting a broader range of viewpoints but also increased variability. This suggests that while a diverse crowd may help reduce bias, it can also result in less predictable assessments.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The traditional use of active RC-type filters as anti-aliasing filters in Pulse Code Modulation (PCM) systems is being replaced by the use of Digital Signal Processing (DSP) filters, especially when performance requirements are tight and when operation over a wide environmental temperature range is required. In order to keep systems more flexible, it is often desired to let the DSP filters run asynchronous to the PCM sample clock. This results in the PCM output signal being a sampling of the output of the DSP, which is itself a sampling of the input signal. In the analysis of the PCM data, the signal will have a periodic repeat of a previous sample, or a missing sample, depending on the relative sampling rates of the DSP and the PCM. This paper analyzes what effects can be expected in the analysis of the PCM data when these anomalies are present. Results are presented which allow the telemetry engineer to make an effective value judgment based on the type of filtering technology to be employed and on the desired system performance.

Sanden international, an automobile air conditioning compressor manufacturer, was facing a problem in its incoming material inspection procedures. Although the company had designed and was using its own sampling plan, some managers and supervisors where not confident of its reliability. Sanden recently established a goal for its total number of defects per supplier as one part per million. Achievement of this target required reviews of the existing sampling plan. The purpose of this project was to help Sandra identify the best alternatives for its incoming material inspection procedures. To do that considerations were made about the usefulness of sampling inspections, theoretical aspects of inspection sampling plans were examined, current sampling plans were analyzed and recommendations were made.

Syfte: Syftet blir att granska vilka vägar det finns för barn och ungdomar att gå för att få möjligheten att representera herr- respektive damlandslaget. Och därefter titta på hur vägen för 41 st lanslagspelare både på herr- och damsidan har sett ut.   Metod: Metoden till denna undersökning har delats upp i två. Den större delen består av en dokumentanalys, där dokument har samlats in och analyserats för att få fram ett resultat. Den andra delen består av en kvalitativ ansats som är två expertintervjuer.   Resultat: Undersökningens resultat visade att det fanns olika vägar att gå för att kunna få möjligheten att representera herr- respektive damlandslaget, de två vanligaste var sampling och tidig specialisering. Variationen var stor bland de manliga fotbollsspelarnas väg till A-landslaget, medan vägarna till A-landslaget för de kvinnliga fotbollsspelarna såg för det mesta likadant ut.   Diskussion: Hur vägarna ser ut till att nå topp eliten och spel i A-landslaget för herr och damer kan bero på olika saker. Fotbollsfostran kan vara en avgörande faktor kring hur din väg kan komma att se ut, beroende på en föreningsfostran eller en tävlingsfostran. / Purpose: The purpose is to review which ways there are for children and young adults to get the opportunity to represent the men's and women's team. And then look at how the ways of 41 national team players have looked like, both men and women.   Method: The method of this survey has been divided into two. The bulk consists of a document analysis, where documents have been collected and analyzed to produce a result. The second part consists of a qualitative approach that is two expert interviews.   Results: The survey results showed that there were different ways to go in order to be able to represent the male and female national teams, the two most common were sampling and early specialization. The variation was great among the male soccer players' path to the A national team, while the roads to the A national team for the female football players looked mostly the same.   Discussion: How the roads seem to reach the top elite and play in the A-national team for men and women can depend on different things. Football education can be a crucial factor in how your route may look, depending on a club education or a contest education.

Em testes nos quais uma quantidade considerável de indivíduos não dispõe de tempo suciente para responder todos os itens temos o que é chamado de efeito de Speededness. O uso do modelo unidimensional da Teoria da Resposta ao Item (TRI) em testes com speededness pode nos levar a uma série de interpretações errôneas uma vez que nesse modelo é suposto que os respondentes possuem tempo suciente para responder todos os itens. Nesse trabalho, desenvolvemos uma análise Bayesiana do modelo tri-dimensional da TRI proposto por Wollack e Cohen (2005) considerando uma estrutura de dependência entre as distribuições a priori dos traços latentes a qual modelamos com o uso de cópulas. Apresentamos um processo de estimação para o modelo proposto e fazemos um estudo de simulação comparativo com a análise realizada por Bazan et al. (2010) na qual foi utilizada distribuições a priori independentes para os traços latentes. Finalmente, fazemos uma análise de sensibilidade do modelo em estudo e apresentamos uma aplicação levando em conta um conjunto de dados reais proveniente de um subteste do EGRA, chamado de Nonsense Words, realizado no Peru em 2007. Nesse subteste os alunos são avaliados por via oral efetuando a leitura, sequencialmente, de 50 palavras sem sentidos em 60 segundos o que caracteriza a presença do efeito speededness. / In tests where a reasonable amount of individuals does not have enough time to answer all items we observe what is called eect of Speededness. The use of a unidimensional model from Item Response Theory (IRT) in tests with speededness can lead us to erroneous interpretations, since this model assumes that the respondents have enough time to answer all items. In this work, we propose a Bayesian analysis of the three-dimensional item response models (IRT) proposed by Wollack and Cohen et al (2005) considering a dependency structure between the prior distributions of the latent traits which is modeled using Copulas. We propose and develop a MCMC algorithm for the estimation of the model. A simulation study comparing with the analysis in Bazan et al (2010), wherein an independent prior distribution assumption was presented. Finally, we apply our model in a set of real data from EGRA, called Nonsense Words, held in Peru in 2007, where students are evaluated for their performance in reading.