Thesis (M.A.)--Boston University

Statistically more test samples obtained from a single chip would give a better picture of the various noise processes present. Increasing the number of samples while testing one chip would however lead to an increase in the testing time, decreasing the overall throughput. The aim of this report is to investigate the detection of non-Gaussian noise (burst noise) in a random set of data with a small number of samples. In order to determine whether a given set of noise samples has non-Gaussian noise processes present, a Chi-Squared ‘Goodness of Fit’ test on a modeled set of random data is presented. A discussion of test methodologies using a single test measurement pass as well as two passes is presented from the obtained simulation results. / text

The human cytomegalovirus (CMV) is one of the viruses which extensively infect in the world. In order to grow and reproduce, the CMV invades designated cellular lives and influences their behavior. The origin of replication (also called the replication origin) is a particular sequence in the CMV DNA genome at which replication is initiated. In this study, we develop some statistical tests of complementary palindromes, which can be applied to narrow the search for replication origin of the CMV DNA sequence. Let X_(2k) be the number of complementary palindromes with length 2k and Y_(2k) be the number of non-covered complementary palindromes with length 2k inside a given DNA sequence. Consider the null hypothesis that the marginal probabilities of the four nucleotides remain the same (1/4) over the given sequence versus the alternative hypothesis that the marginal probabilities are different. The likelihood ratio test based on the joint distributions of Y_(18) and Y_(2k) | (Y_(2(k+1)), ...,Y_(18)), where k=1, ..., 8, under the null and the alternative hypotheses are derived. The null distribution of the test statistic is approximated by a scaled chi-squared distribution. The scale parameter and the degree of freedom are estimated by the method of moments. The Pearson's chi-squared test based on the marginal distributions of X_(2k), where k=1, ..., 9. The null distribution of the test statistic is also approximated by a scaled chi-squared distribution. There is an another focus about ratios statistics X_(2k)/X_(2(k+1)) and Y_(2k)/Y_(2(k+1)), which approximate a specific value under the null hypotheses. Simulation studies are performed to confirm the theoretical findings.

Most American universities and colleges require students to provide faculty evaluation at end of each academic term, as a way of measuring faculty teaching performance. Although some analysts think that this kind of evaluation does not necessarily provide a good measurement of teaching effectiveness, there is a growing agreement in the academic world about its reliability. This study attempts to find any strong statistical evidence supporting faculty evaluation by students as a measure of faculty teaching effectiveness. Emphasis will be on analyzing relationships between instructor ratings by students and corresponding students’ grades. Various statistical methods are applied to analyze a sample of real data and derive conclusions. Methods considered include multivariate statistical analysis, principal component analysis, Pearson's correlation coefficient, Spearman's and Kendall’s rank correlation coefficients, linear and logistic regression analysis.

As telhas de cimento-amianto são utilizadas mundialmente nas construções comerciais, residenciais e industriais. O amianto foi a primeira aplicação de fibra natural em escala industrial. Esta fibra foi incorporada na forma do mineral (asbesto) como reforço de matrizes à base do cimento. O processo de fabricação de telhas de cimento-amianto mais utilizado mundialmente foi patenteado em 1900 por Ludwig Hatschek, recebendo o mesmo nome. O objetivo deste trabalho foi a melhoria do processo industrial (Hatschek) de fabricação de telha de cimento-amianto, com o uso de métodos estatísticos. Inicialmente as variáveis mais influentes no processo foram identificadas empregando-se o teste de correlação de Pearson e o Cp de Mallows que permitiu a escolha do melhor subconjunto da regressão (R², R²ajustado, Cp de Mallows e o desvio padrão do modelo). A seleção dessas variáveis permitiu a construção de modelos de regressão para o processo, para as respostas resistência mecânica e densidade da telha. Devido à análise de duas respostas, foi realizada uma otimização numérica por meio da função desejabilidade (desirability function), que é baseada na idéia de que a qualidade de um produto ou processo que tem múltiplas respostas depende de encontrar as variações do processo que atendem a todas as restrições impostas, sejam elas econômicas ou normas aplicáveis ao produto final. Com o resultado da otimização estabeleceram-se faixas de variação das variáveis mais influentes, que permitissem a operação do processo sob controle. Também, pode ser concluído que para a densidade de ambas as telhas (5 mm e 6 mm) encontraram-se modelos coerentes para serem usados mesmo após alguma modificação na máquina, enquanto que para a resistência os parâmetros dos modelos devem ser reajustados sempre que houver alguma modificação durante a parada da máquina. / Roofing tiles of the asbestos cement composites are used world-wide in the commercial, residential and industrial constructions. Asbestos was the first natural fiber application in industrial scale. This fiber was incorporated into the cimentitious matrices to overcome this weakness. The manufacturing process of asbestos-cement tiles most commonly used worldwide was patented in 1900 by Ludwig Hatschek, which gave his own name to this procedure. Considering that, this study aimed to improve the manufacturing process of roofing tiles of the asbestos cement composites, using several statistical methods. Firstly, the most influent variables were identified using the Pearson Correlation test and the Mallows Cp test, which provided the choice of the best subsets regression (R ², R ² adjusted, Mallows Cp and the standard deviation of this empirical model). The selection of these variables allowed the construction of regression models for the mechanical resistance and tile density responses. In order to fulfill the requirement of an appropriate analysis for two responses, a numerical optimization by means of desirability function was applied. This optimization is based on the premise that a product quality or process having multiple responses depends on finding all the variations that fulfill the imposed constraints. Even if these constraints were economic or norms applied to the final product. The optimization results established ranges of variation including the most influents variables, i.e., the ones that allow the process to run under control. Also, we conclude that for the density of both tiles (5 mm and 6 mm) were found consistent models to be used even after some eventual change in machine. For the resistance, however, the parameters of the models must be readjusted whenever it has some modification during the shutdown of the machine.

Objetivo. Comparar, teórica e empiricamente, dois estimadores do coeficiente de correlação intraclasse momento-produto de Pearson para pares repetidos Pi. O primeiro é o estimador \"natural\", obtido mediante a correlação momento-produto de Pearson para membros de uma mesma classe (rI) e o segundo, obtido como função de componentes de variância (icc). Métodos. Comparação teórica e empírica dos parâmetros e estimadores. A comparação teórica envolve duas definições do coeficiente de correlação intraclasse PI como medida de confiabilidade (*), para o caso de duas réplicas, assim como uma apresentação da técnica de análise de variância e a definição e interpretação dos estimadores ri e icc. A comparação empírica é realizada mediante um estudo de simulação Monte Carlo com a geração de pares de valores correlacionados segundo o coeficiente de correlação intraclasse, momento-produto de Pearson para pares repetidos. Os pares de valores são distribuídos segundo uma distribuição Normal bivariada, com valores do tamanho da amostra e da correlação intraclasse previamente fixados em: n= 15, 30 e 45 e pI = {O; 0,15; 0,30; 0,45; 0,60; 0,75; 0,9}. Resultados. Comparando-se o vício e o erro quadrático médio dos estimadores, bem como as amplitudes dos intervalos de confiança, tem-se como resultado que o vício de icc foi sempre menor que o vício de rI, mesmo ocorrendo com o erro quadrático médio. Conclusões. O icc é um estimador melhor, principalmente para n pequeno (por exemplo 15). Para valores maiores de n (30 ou mais), os estimadores produzem resultados iguais até a segunda casa decimal. / Objective. This thesis presents and compares, theoretically and empirically, two estimators of the intraclass correlation coefficient pI, defined as Pearson\'s pairwise intraclass correlation coefficient. The first is the \"natural\" estimator, obtained by Pearson\'s moment-product correlation for members of one class (rI) while the second was obtained as a function of components of variance (icc). Methods. Theoretical and empirical comparison of the parameters and estimators are performed. The theoretical comparison involves two definitions of the intrac1ass correlation coefficient pI as a measure of reliability (*) for two repeated measurements in the same class and the presentation of the technique of analysis of variance, as well as for the definition and interpretation of the estimators ri and icc. The empirical comparison was carried out by means of a Monte Carlo simulation study of pairs of correlated values according Pearson\'s pairwise correlation. The pairs of values follow a normal bivariate distribution, with correlation values and sample size previously fixed: n= 15, 30 e 45 and Pl = . Results. Bias and mean square error for the estimators were compared as well as the range of the intervals of confidence. The comparison shows that the bias of icc is always smaller than of rI This also applies to the mean square error. Conclusions. The icc is a better estimator, especially for n less than or equal to 15. For larger samples sízes (n 30 or more), the estimators produce results that are equal to the second decimal place. (*) Fórmula

As telhas de cimento-amianto são utilizadas mundialmente nas construções comerciais, residenciais e industriais. O amianto foi a primeira aplicação de fibra natural em escala industrial. Esta fibra foi incorporada na forma do mineral (asbesto) como reforço de matrizes à base do cimento. O processo de fabricação de telhas de cimento-amianto mais utilizado mundialmente foi patenteado em 1900 por Ludwig Hatschek, recebendo o mesmo nome. O objetivo deste trabalho foi a melhoria do processo industrial (Hatschek) de fabricação de telha de cimento-amianto, com o uso de métodos estatísticos. Inicialmente as variáveis mais influentes no processo foram identificadas empregando-se o teste de correlação de Pearson e o Cp de Mallows que permitiu a escolha do melhor subconjunto da regressão (R², R²ajustado, Cp de Mallows e o desvio padrão do modelo). A seleção dessas variáveis permitiu a construção de modelos de regressão para o processo, para as respostas resistência mecânica e densidade da telha. Devido à análise de duas respostas, foi realizada uma otimização numérica por meio da função desejabilidade (desirability function), que é baseada na idéia de que a qualidade de um produto ou processo que tem múltiplas respostas depende de encontrar as variações do processo que atendem a todas as restrições impostas, sejam elas econômicas ou normas aplicáveis ao produto final. Com o resultado da otimização estabeleceram-se faixas de variação das variáveis mais influentes, que permitissem a operação do processo sob controle. Também, pode ser concluído que para a densidade de ambas as telhas (5 mm e 6 mm) encontraram-se modelos coerentes para serem usados mesmo após alguma modificação na máquina, enquanto que para a resistência os parâmetros dos modelos devem ser reajustados sempre que houver alguma modificação durante a parada da máquina. / Roofing tiles of the asbestos cement composites are used world-wide in the commercial, residential and industrial constructions. Asbestos was the first natural fiber application in industrial scale. This fiber was incorporated into the cimentitious matrices to overcome this weakness. The manufacturing process of asbestos-cement tiles most commonly used worldwide was patented in 1900 by Ludwig Hatschek, which gave his own name to this procedure. Considering that, this study aimed to improve the manufacturing process of roofing tiles of the asbestos cement composites, using several statistical methods. Firstly, the most influent variables were identified using the Pearson Correlation test and the Mallows Cp test, which provided the choice of the best subsets regression (R ², R ² adjusted, Mallows Cp and the standard deviation of this empirical model). The selection of these variables allowed the construction of regression models for the mechanical resistance and tile density responses. In order to fulfill the requirement of an appropriate analysis for two responses, a numerical optimization by means of desirability function was applied. This optimization is based on the premise that a product quality or process having multiple responses depends on finding all the variations that fulfill the imposed constraints. Even if these constraints were economic or norms applied to the final product. The optimization results established ranges of variation including the most influents variables, i.e., the ones that allow the process to run under control. Also, we conclude that for the density of both tiles (5 mm and 6 mm) were found consistent models to be used even after some eventual change in machine. For the resistance, however, the parameters of the models must be readjusted whenever it has some modification during the shutdown of the machine.

Objetivo. Comparar, teórica e empiricamente, dois estimadores do coeficiente de correlação intraclasse momento-produto de Pearson para pares repetidos Pi. O primeiro é o estimador \"natural\", obtido mediante a correlação momento-produto de Pearson para membros de uma mesma classe (rI) e o segundo, obtido como função de componentes de variância (icc). Métodos. Comparação teórica e empírica dos parâmetros e estimadores. A comparação teórica envolve duas definições do coeficiente de correlação intraclasse PI como medida de confiabilidade (*), para o caso de duas réplicas, assim como uma apresentação da técnica de análise de variância e a definição e interpretação dos estimadores ri e icc. A comparação empírica é realizada mediante um estudo de simulação Monte Carlo com a geração de pares de valores correlacionados segundo o coeficiente de correlação intraclasse, momento-produto de Pearson para pares repetidos. Os pares de valores são distribuídos segundo uma distribuição Normal bivariada, com valores do tamanho da amostra e da correlação intraclasse previamente fixados em: n= 15, 30 e 45 e pI = {O; 0,15; 0,30; 0,45; 0,60; 0,75; 0,9}. Resultados. Comparando-se o vício e o erro quadrático médio dos estimadores, bem como as amplitudes dos intervalos de confiança, tem-se como resultado que o vício de icc foi sempre menor que o vício de rI, mesmo ocorrendo com o erro quadrático médio. Conclusões. O icc é um estimador melhor, principalmente para n pequeno (por exemplo 15). Para valores maiores de n (30 ou mais), os estimadores produzem resultados iguais até a segunda casa decimal. / Objective. This thesis presents and compares, theoretically and empirically, two estimators of the intraclass correlation coefficient pI, defined as Pearson\'s pairwise intraclass correlation coefficient. The first is the \"natural\" estimator, obtained by Pearson\'s moment-product correlation for members of one class (rI) while the second was obtained as a function of components of variance (icc). Methods. Theoretical and empirical comparison of the parameters and estimators are performed. The theoretical comparison involves two definitions of the intrac1ass correlation coefficient pI as a measure of reliability (*) for two repeated measurements in the same class and the presentation of the technique of analysis of variance, as well as for the definition and interpretation of the estimators ri and icc. The empirical comparison was carried out by means of a Monte Carlo simulation study of pairs of correlated values according Pearson\'s pairwise correlation. The pairs of values follow a normal bivariate distribution, with correlation values and sample size previously fixed: n= 15, 30 e 45 and Pl = . Results. Bias and mean square error for the estimators were compared as well as the range of the intervals of confidence. The comparison shows that the bias of icc is always smaller than of rI This also applies to the mean square error. Conclusions. The icc is a better estimator, especially for n less than or equal to 15. For larger samples sízes (n 30 or more), the estimators produce results that are equal to the second decimal place. (*) Fórmula

Thesis(M.Sc. (Animal Production)) -- University of Limpopo, 2022 / Donkeys continue to play a significant role in draught power activities for both rural and urban regions in underdeveloped countries, where they are commonly employed for transportation of goods and movement of people at extremely low prices. The study sought to determine donkey farmers' breeding practices as well as donkey morphological characterization in three villages such as Thorp, Archibalt and Genau of the Blouberg Local Municipality. A total of 21 donkey farmers and 74 donkeys were used to collect data. The following Morphological traits characterized were; Head length (HL), Ear length (EL), Neck length (NL), Chest width (CW), Back length (Bal), Body length (BoL), Hips width (HW), Umbilical circumference (UC), Back height (BH), Height at the rump (HR), Thoracic circumference (TC), Chest depth (CD), Withers Height (WH), Front leg length (FLL), Cannon circumference (CC), Cannon length (CL), Cannon height (CH) and Body weight (BW). Descriptive statistics, Chi-square tests, Analysis of variance (ANOVA), Pearson correlation, and Rank Index were used for data analysis. Education level of the farmers in the three villages was significantly different (p<0.05) with the majority of farmers having secondary education. There was no significant difference (p>0.05) amongst the villages on different reasons behind keeping donkeys. The results showed a significant difference (p<0.05) in inbreeding knowledge by the farmers amongst the three villages. The selection criteria used across the three villages were not significantly different (p>0.05). Rank and Indices in selection of male donkeys looked at body size (0.39), growth rate (0.19), Draught power performance (0.14), and for overall preference in female donkeys it was body size (0.26), twinning ability (0.23) and mothering ability (0.15). Body size and growth rate where the most important traits to donkey farmers. The coat colours were not significantly different (p>0.05). In all the eighteen measured traits, only four (BaL, HW, BH and FLL) showed a significant difference (p<0.05) among the three villages. BW in male donkeys was not significantly correlated (p>0.05) with HL, EL, NL, BaL, HW, FLL, CC, CH, CL but was positively correlated (p<0.05) with BoL (r = 0.34), UC (r = 0.35), TC (r = 0.33), CD (r = 0.31), CW (0.94), BH (r = 0.41), HR (0.60), and WH (r = 0.58). BW in female donkeys was not significantly correlated (p>0.05) with NL, BaL, TC, and CL but positively significant correlated (p<0.05) with HL, EL, BoL, HW, UC, FLL and CC CW, BH, HR, WH and CH with correlation coefficient values ranging from 0.34 to 0.75. The farmers had no breeding program in place the donkeys were allowed to mate on their own without designed breeding program. Selection of donkeys to be part of the heard was based on physical attributes, such length It was concluded that donkey farmers in Genau, Archibalt, and Thorp villages engaged in breeding practices that could be valuable in construction of a community-based breeding program.

- 6 - Abstract Title: Comparison of performance tests results determined during kayak spiroergometry with achieved kayak paddling performance. Objectives: The aim of the study was to determine relationships between functional parameters values found during kayak spiroergometry and sport performance at 1000 meters distance, and how are these relationships going to change based on training period. Methods: To determine statistical dependence between sport performance at 1000 meters distance and choosen factors of sport performance, the correlation research was used - as a variable-dependent value the final result of sport performance at 1000 meters distance was used, as a variable-independent amounts functional parameters values found during kayak spiroergometry were used. To discover the statistical dependence methods of Pearson's correlation coefficient and regression analysis were used. Results: General level of kayak-athletes from testing file indicated by functional parameters values and demonstrated by kayak spiroergometry performance depends on kayak- athlete's level of sport performance at 1000 meters distance in prepared-training period only, when importance for general condition is emphasized. We did not discover the same phenomenon based on pre-racing period testing results. Sport performance at...