Zugl.: Hamburg, Universiẗat, Diss., 2007.

More retail and service firms are using mystery shoppers in Taiwan to monitor their frontline operations and to assess their customer service, since the concern over whether their customers are truly satisfied is increasing. However, virtually nothing is known about whether the quality of the data collected by professional mystery shoppers is different or more reliable than that of shoppers disguised by general customers. Here we use a traditional statistics approach to assess the quality of data collected from both professional mystery shoppers and general customers. Feedback questionnaires from general customers and the potential use of mystery shoppers are made as a means of evaluating the service quality of cram schools in Taiwan. The purpose of this thesis is to show that the reliability of mystery shopping data made from professional mystery shoppers is higher than that of data made from general customers. With this question in mind, we conducted a two-step empirical research, as the amount of samples needed was insufficient. First, a primary study to examine the equality of population among branches was carried out in order to pool data from different branches. Then, the relative reliability of the surveys of mystery shoppers to general customers was examined by pooling data of the branches together. The findings provide evidence to suggest that reliable information could be obtained by pooling both shopper reports together. This empirical result also implied that well-trained mystery shoppers can make more objective observations and more effective assessments than general customers.

The American Association of Highway and Transportation Officials (AASHTO) and Federal Highway Administration (FHWA) require the use of the statistically based quality assurance (QA) specifications for construction materials. As a result, many of the state highway agencies (SHAs) have implemented the use of a QA specification for highway construction. For these statistically based QA specifications, quality characteristics of most construction materials are assumed normally distributed, however, the normality assumption can be violated in several forms. Distribution of data can be skewed, kurtosis induced, or bimodal. If the process shows evidence of a significant departure from normality, then the quality measures calculated may be erroneous. In this research study, an extended QA data analysis model is proposed which will significantly improve the Type I error and power of the F-test and t-test, and remove bias estimates of Percent within Limit (PWL) based pay factor calculation. For the F-test, three alternative tests are proposed when sampling distribution is non-normal. These are: 1) Levene’s test; 2) Brown and Forsythe’s test; and 3) O’Brien’s test. One alternative method is proposed for the t-test, which is the non-parametric Wilcoxon - Mann – Whitney Sign Rank test. For PWL based pay factor calculation when lot data suffer non-normality, three schemes were investigated, which are: 1) simple transformation methods, 2) The Clements method, and 3) Modified Box-Cox transformation using “Golden Section Search” method. The Monte Carlo simulation study revealed that both Levene’s test and Brown and Forsythe’s test are robust alternative tests of variances when underlying sample population distribution is non-normal. Between the t-test and Wilcoxon test, the t-test was found significantly robust even when sample population distribution was severely non-normal. Among the data transformation for PWL based pay factor, the modified Box-Cox transformation using the golden section search method was found to be the most effective in minimizing or removing pay bias. Field QA data was analyzed to validate the model and a Microsoft® Excel macro based software is developed, which can adjust any pay consequences due to non-normality.

The linear mixed model is widely implemented in the analysis of longitudinal data. Inference techniques and information criteria are available and well-studied for goodness-of-fit within the linear mixed model setting. Predictive approaches such as R-squared, PRESS, and CCC are available for the linear mixed model but require more research (Edward, 2005). This project used simulation to investigate the performance of R-squared, PRESS, CCC, Pseudo F-test and information criterion for goodness-of-fit within the linear mixed model framework. Marginal and conditional approaches for these predictive statistics were studied under different variance-covariance structures. For compound symmetry structure, the success rates for all 17 statistics (marginal and conditional R-squared, PRESS, CCC, F test, AIC and BIC) were high. The study suggested using marginal rather than conditional residuals for PRESS, CCC and R-squared. It suggested using REML likelihood function which has the determinant term for AIC and BIC. For CCC, R-squared, and the information criterion, there was no difference for the various parameter number adjustments. For autoregressive order 1 plus random effect, the study suggested using conditional residuals for PRESS, marginal residuals for CCC and R-squared, and using REML function with the determinant term for AIC and BIC. Also there was no difference for the different parameter number adjustments. The F-test performed well for all covariance structures. The study also indicated that characteristics of the data, such as the covariance structure, parameter values, and sample size, can greatly impact performance of various statistics. No one criterion is consistently better than the others in terms of selection performance in the simulation study.

The aim of the thesis is to evaluate whether is there a convergence in the tax systems of the EU Member States or not. The first chapter describes a development in a process of tax coordination and harmonization of the EU Member States. The next chapter focuses on a description and comparison of the current state of the tax systems in the European Union. The third chapter deals with the statistical evaluation of the development of individual variables - overall tax quota, tax quota of individual taxes, implicit tax rates, statutory tax rates, for individual taxes and a group of taxes between 1995 and 2011 period. The fourth chapter summarizes the results of the analysis.

Experiments with broiler chickens are common today, because due to the great market demand for chicken meat, the need to improve the factors related to the production of broiler chicken has arisen. Many studies have been done to improve handling techniques. In these studies statistical analysis methods and techniques are employed. In studies with comparisons between treatments, it is not uncommon to observe a lack of significant effect even when there is evidence to indicate the significance of the effects. In order to avoid such eventualities it is fundamental to carry out a good planning before conducting the experiment. In this context, a study of the power of the F test was made emphasizing the relationships between test power, sample size, mean difference to be detected and variance for chicken weights data. In the analysis of data from experiments with broilers with mixed sexes and that the experimental unit is the box, generally the models used do not take into account the variability between the sexes of the birds, this affects the precision of the inference on the population of interest . We propose a model for the total weight per box that takes into account the sex information of the broiler chickens. / Experimentos com frangos de corte são comuns atualmente, pois devido à grande demanda de mercado da carne de frango surgiu a necessidade de melhorar os fatores ligados à produção do frango de corte. Muitos estudos têm sido feitos para aprimorar as técnicas de manejo. Nesses estudos os métodos e técnicas estatísticas de análise são empregados. Em estudos com comparações entre tratamentos, não é incomum observar falta de efeito significativo mesmo quando existem evidências que apontam a significância dos efeitos. Para evitar tais eventualidades é fundamental realizar um bom planejamento antes da condução do experimento. Nesse contexto, foi feito um estudo do poder do teste F enfatizando as relações entre o poder do teste, tamanho da amostra, diferença média a ser detectada e variância para dados de pesos de frangos. Na análise de dados provenientes de experimentos com frangos de corte com ambos os sexos e que a unidade experimental é o boxe, geralmente os modelos utilizados não levam em conta a variabilidade entre os sexos das aves, isso afeta a precisão da inferência sobre a população de interesse. Foi proposto um modelo para o peso total por boxe que leva em conta a informação do sexo dos frangos.

O presente trabalho teve por objetivos propor um método alternativo para testar a contribuição de cada genótipo, local e ano para a interação genótipos × locais × anos por meio de um teste F, em dados provenientes de experimentos agronômicos e implementar uma rotina computacional para a realização da análise de dados, mediante a contribuição de cada genótipo, local e ano para a interação. O estudo avalia treze genótipos e nove ambientes (combinação de três locais e três anos). Simulou-se as somas de quadrados das fatias horizontais (genótipos), verticais (locais) e frontais (anos) do arranjo de três entradas de interação genótipos × locais × anos (G×L×A) gerando 500, 1000 e 5000 experimentos para verificar a distribuição empírica. Os resultados indicaram um ajuste à distribuição qui-quadrado não-central para as fatias horizontais, verticais e frontais do arranjo de três entradas de interação G×L×A, verificados também pelo teste de Kolmogorov-Smirnov e o gráfico QQplot. Na aplicação do teste F proposto, identificou-se os genótipos, locais e anos que contribuem mais para a interação genótipos × locais × anos, sendo de fácil aplicação e interpretação. / The present study objectives is to demonstrate an alternative method for test factor con- tribution on a triple interaction system segregating environment effects (locations × years) and genotypes effect. The analysis consists of two parts: (1) a F test, applied in agronomical experiments for means calculation; and (2) the implementation of a computer routine for simulating experiments and check results with the proposed method. The triple interaction (genotypes × locations × years) was studied in thirteen genotypes and nine environments (a combination of three locations and three years), in a block design with three repetitions. The sum of squares within horizontal slices (genotypes), vertical slices (locations) and frontal slices (years) of three way array the genotypes × locations × years (G×L×A) were simulated, generating 500, 1000 and 5000 experiments to test the empirical distribution. The results indicates a non-central chi-squared distribution for horizontal, vertical and frontal slices in the three way array G×L×A, also was tested using the Kolmogorov-Smirnov test and QQplot plot. The application of F test identified the genotypes, locations and years showing the relative contribution of these factors for the triple interaction (genotypes × locations × years), getting an easy routine and fast interpretation method.

Experiments with broiler chickens are common today, because due to the great market demand for chicken meat, the need to improve the factors related to the production of broiler chicken has arisen. Many studies have been done to improve handling techniques. In these studies statistical analysis methods and techniques are employed. In studies with comparisons between treatments, it is not uncommon to observe a lack of significant effect even when there is evidence to indicate the significance of the effects. In order to avoid such eventualities it is fundamental to carry out a good planning before conducting the experiment. In this context, a study of the power of the F test was made emphasizing the relationships between test power, sample size, mean difference to be detected and variance for chicken weights data. In the analysis of data from experiments with broilers with mixed sexes and that the experimental unit is the box, generally the models used do not take into account the variability between the sexes of the birds, this affects the precision of the inference on the population of interest . We propose a model for the total weight per box that takes into account the sex information of the broiler chickens. / Experimentos com frangos de corte são comuns atualmente, pois devido à grande demanda de mercado da carne de frango surgiu a necessidade de melhorar os fatores ligados à produção do frango de corte. Muitos estudos têm sido feitos para aprimorar as técnicas de manejo. Nesses estudos os métodos e técnicas estatísticas de análise são empregados. Em estudos com comparações entre tratamentos, não é incomum observar falta de efeito significativo mesmo quando existem evidências que apontam a significância dos efeitos. Para evitar tais eventualidades é fundamental realizar um bom planejamento antes da condução do experimento. Nesse contexto, foi feito um estudo do poder do teste F enfatizando as relações entre o poder do teste, tamanho da amostra, diferença média a ser detectada e variância para dados de pesos de frangos. Na análise de dados provenientes de experimentos com frangos de corte com ambos os sexos e que a unidade experimental é o boxe, geralmente os modelos utilizados não levam em conta a variabilidade entre os sexos das aves, isso afeta a precisão da inferência sobre a população de interesse. Foi proposto um modelo para o peso total por boxe que leva em conta a informação do sexo dos frangos.

Forty songs are randomly selected from four randomly selected maqams. Songs are restricted to be in sofyan us&uuml / l (sofyan rhythmic form) to check the statistical significance. Next, fractal dimensions of the these songs are calculated by using two different method and two different scattering diagrams. In the first method, fractal dimensions are calculated via two different box sizes. As for second method, successively decreased box sizes are used. In addition, standard deviation and mean values of the fractal dimensions are calculated to check the relation between fractal dimension and maqam. T test and F test are applied to check the statistical significance. After these calculations, it is verified that fractal dimension can be used as an information source concerning the Turkish art music songs which are nonlinear dynamical systems. Moreover, it is showed that maqams can have their own fractal dimension for low resolutions. On the other hand, it is seen that for high resolutions all songs have almost same fractal dimension.

This thesis is concerned on the theme Milk and dairy products in nutrition of pupils aged 11 to 15 years. The theoretical part is based on the chemical composition of milk of general aspect and there are characterized some chosen kinds of dairy products and their effects on human health. The practical part is concerned on the research of being some statistically significant differences in consumption of milk and dairy products of the point of view of gender, age and access to milk and diary products in the families. The research is further based on the finding of the levels of probands'knowledge about the composition and the influence of milk to the human organism. The research sample is formed by 240 pupils of Secondary school in Domažlice, Komenského 17. The results show neither the gender, age or access to milk and diary products in the families do not affect the consumption of milk and dairy products of individual probands. The education unit whose aim is to increase the knowledge about milk of second graders in elementary schools is proposed on basis of identified facts.