Inaug - Diss. - Gottingen.

Master of Science / Department of Statistics / Weixing Song / The goal of this report is to compare various estimation procedures on regression models in which the dependent variable has a restricted range. These models, called Tobit models, are seeing an increase in use among economists and market researchers, specifically. Only the standard Tobit regression model is discussed in the report. First we will examine the five estimation methods discussed in Amemiya (1984) for standard Tobit model. These methods include Probit maximum likelihood, least squares, Heckman’s two-step, Tobit maximum likelihood, and the EM algorithm. We will examine the algorithm utilized in each method’s estimation process. We will then conduct simulation studies using these estimation procedures. Twelve scenarios have been considered consisting of three different truncation threshold on the response variable, two distributions of covariates, and the error variance known and unknown. The results are reported and a discussion of the goodness of each method follows. The study shows that the best method for estimating Tobit regression models is indeed the Tobit maximum likelihood estimation. Heckman’s two-step method and the EM algorithm also estimate these models well when the truncation rate is low and the sample size is large. The simulation results show that the Least squares estimation procedure is far less efficient than other estimation procedures.

This thesis provides a unique perspective to the milk market relative to previous studies. While there is rich literature on the various sectors of the milk market, a contribution to this literature was made by providing a specific econometric analysis of the Promised Land brand. Previous work conducted by Capps and Salin (2010) provided the foundation for this thesis. The purpose of this thesis was threefold: 1. Estimate household demand functions for Promised Land white and chocolate milk using Nielsen homescan data. The demand functions were estimated using a tobit model to estimate the conditional and unconditional own-price and cross-price effects of Promised Land white and chocolate milk. 2. Assess the impacts of household demographic drivers of demand for Promised Land white and chocolate milk. 3. Use the empirical results derived from the tobit model to identify substitutes and complements of Promised Land white and chocolate milk and provide a profile of households that purchase Promised Land white and chocolate milk. The study concluded that households who purchased Promised Land white were insensitive to changes in the price of Promised Land white milk. The price of private label milk was the only cross-price that was significant in the quantity of Promised Land white milk purchased. The estimated elasticities showed that Promised Land white milk and private label white milk were substitutes. From the estimated elasticities, it was found that households that purchased Promised Land chocolate milk were largely insensitive to changes in the price of Promised Land chocolate milk. It was also found that the prices of Nesquick, Oak Farms, and private label chocolate milk had a significant effect on the quantity of Promised Land chocolate milk purchased. Of these significant prices, private label and Oak Farms chocolate milk were substitutes for Promised Land chocolate milk. The price of Nesquick chocolate milk demonstrated a complementary relationship with Promised Land chocolate milk.

Habilitationsschrift--Mainz. / Bibliography: p. 317-[346].

Habilitationsschrift--Mainz. / Bibliography: p. 317-[346]

<p>Denna uppsats undersöker om det finns några skillnader mellan könen i medaljtagande under de olympiska spelen med avseende på ett antal socioekonomiska faktorer. Vi skattar en modell med tobitmetoden och finner att kvinnor i jämförelse med män får en större positiv effekt i länder med hög befolkning, medan de får en större negativ effekt i länder med hög fertilitet samt en lägre positiv effekt i hemmanationer. Däremot finner vi inga skillnader med avseende på BNP per capita, länder som tillhörde Comecon och kvinnligt arbetskraftsdeltagande. Avslutningsvis gör vi en skattning av antalet medaljer olika länder kommer att ta under Peking-OS 2008.</p>

Master of Science / Department of Statistics / Weixing Song / In the classical Tobit regression model, the regression error term is often assumed to have a zero mean normal distribution with unknown variance, and the regression function is assumed to be linear. If the normality assumption is violated, then the commonly used maximum likelihood estimate becomes inconsistent. Moreover, the likelihood function will be very complicated if the regression function is nonlinear even the error density is normal, which makes the maximum likelihood estimation procedure hard to implement. In the full nonparametric setup when both the regression function and the distribution of the error term [epsilon] are unknown, some nonparametric estimators for the regression function has been proposed. Although the assumption of knowing the distribution is strict, it is a widely adopted assumption in Tobit regression literature, and is also confirmed by many empirical studies conducted in the econometric research. In fact, a majority of the relevant research assumes that [epsilon] possesses a normal distribution with mean 0 and unknown standard deviation. In this report, we will try to develop a semi-parametric estimation procedure for the regression function by assuming that the error term follows a distribution from a class of 0-mean symmetric location and scale family. A minimum distance estimation procedure for estimating the parameters in the regression function when it has a specified parametric form is also constructed. Compare with the existing semiparametric and nonparametric methods in the literature, our method would be more efficient in that more information, in particular the knowledge of the distribution of [epsilon], is used. Moreover, the computation is relative inexpensive. Given lots of application does assume that [epsilon] has normal or other known distribution, the current work no doubt provides some more practical tools for statistical inference in Tobit regression model.

Remittances significantly affect recipient households’ behavior. Using data from the Jamaican Survey of Living Conditions and the Jamaican Labor Force Survey ( 2001-2007), this dissertation explores the effects of remittances on labor market participation and household expenditures. Jamaica’s proximity to the United States and its diaspora of educated individuals shapes an economy largely dependent on remittances, thus providing an interesting case study. First, we investigate whether remittances alter labor market behavior of married women in remittance-receiving households located in Jamaica. Remittances, the wife’s education, and wages are all treated as endogenous when estimating labor market participation and hours worked. Unlike other studies, we find that after instrumenting for remittances, the outside income has no significant effect on the supply of labor. Second, we assess the extent that remittances alter the consumption pattern of recipient households in Jamaica. Classical theory predicts that total income affects household consumption decisions, but developments in behavioral economics suggest otherwise. The disaggregation of income streams and consumption expenditures provide us with unique insight into household behavior and in particular, spending on items such as food, schooling, and vices. Using Engel curve estimation and the two-part fractional response models, we find that the source of income significantly affects the shares of income spent in specific consumption categories. Recipients, for example, generally spend more of their income on schooling and home production and less at the grocery store. These findings suggest important implications should government look to tax or restrict the flow of remittances.

Denna uppsats undersöker om det finns några skillnader mellan könen i medaljtagande under de olympiska spelen med avseende på ett antal socioekonomiska faktorer. Vi skattar en modell med tobitmetoden och finner att kvinnor i jämförelse med män får en större positiv effekt i länder med hög befolkning, medan de får en större negativ effekt i länder med hög fertilitet samt en lägre positiv effekt i hemmanationer. Däremot finner vi inga skillnader med avseende på BNP per capita, länder som tillhörde Comecon och kvinnligt arbetskraftsdeltagande. Avslutningsvis gör vi en skattning av antalet medaljer olika länder kommer att ta under Peking-OS 2008.

SOUSA, Daniel Tomaz de. Múltiplo emprego no Brasil: uma análise da oferta de trabalho usando dados da PNAD / Daniel Tomaz de Sousa. - 2017. 38 f. Dissertação (Mestrado) – Universidade Federal do Ceará, Faculdade de Economia, Administração, Atuária e Contabilidade, Programa de Pós-Graduação em Economia, Fortaleza, 2017. / Submitted by Mônica Correia Aquino (monicacorreiaaquino@gmail.com) on 2017-09-21T21:01:25Z No. of bitstreams: 1 2017_dis_dtsousa.pdf: 783806 bytes, checksum: 4158497937d214cf6e43e24350ed6f3d (MD5) / Approved for entry into archive by Mônica Correia Aquino (monicacorreiaaquino@gmail.com) on 2017-09-21T21:01:40Z (GMT) No. of bitstreams: 1 2017_dis_dtsousa.pdf: 783806 bytes, checksum: 4158497937d214cf6e43e24350ed6f3d (MD5) / Made available in DSpace on 2017-09-21T21:01:40Z (GMT). No. of bitstreams: 1 2017_dis_dtsousa.pdf: 783806 bytes, checksum: 4158497937d214cf6e43e24350ed6f3d (MD5) Previous issue date: 2017 / The present study has as objective to analyze the determinants of labor supply in the secondary labor market in Brazil. An agent is said to belong to the secondary labor market when he spends hours working in a second occupation, in addition to having a primary job. To reach the objective, data from the National Household Sample Survey (PNAD), from 2004 and 2014, were used and a model with a limited dependent variable, tobit, was used in addition to the descriptive analysis. The results indicate that the market in question is composed mostly of men, heads of families and workers who have a higher educational level when compared to those with only one occupation. Individuals in the secondary market have a salary advantage in the main occupation and spend fewer hours per week in the main job. From the estimated supply function, it is shown that male individuals offer more hours of work, a result that is in agreement with part of the international literature. Age is positively related to an offer, in addition to having a main occupation in the private, formal, migrant and residing metropolitan areas, they have a negative impact. From the theoretical viewpoints tested, the reason for restricting hours to the effect and reduced the supply, already the reason for age insecurity in the opposite direction expected, increasing a job offer. The results of this study reinforce the importance of this part of the Brazilian labor market, also reducing the gaps in this area of research and reiterates the importance of socioeconomic variables in the determination of supply. / O presente estudo tem como objetivo analisar os determinantes da oferta de trabalho no mercado secundário no Brasil. Diz-se que um agente pertence ao mercado de trabalho secundário quando dedica horas de trabalho em uma segunda ocupação, além de possuir um emprego principal. Para atingir o objetivo, foram utilizados dados da Pesquisa Nacional por Amostra de Domicílios (PNAD), dos anos de 2004 e 2014, e fez-se uso de um modelo com variável dependente limitada, tobit, além da análise descritiva. Os resultados indicam que o mercado em análise é composto em sua maioria por homens, chefes de famílias e trabalhadores que possuem um nível educacional mais elevado, quando comparados com aqueles que possuem apenas uma ocupação. Indivíduos alocados no mercado secundário possuem vantagem salarial na ocupação principal e passam menos horas por semana no emprego principal. Da função oferta estimada, tem-se que indivíduos do sexo masculino ofertam mais horas de trabalho, resultado corrobora com parte da literatura internacional. Idade relaciona-se de forma positiva com a oferta, ademais ter ocupação principal no setor privado, formal, ser migrante e residir em região metropolitana impactam de forma negativa. Dos aspectos teóricos testados, o motivo restrição de horas foi relevante e reduz a oferta, já o motivo insegurança atua no sentido contrário do esperado, aumentando a oferta de trabalho. Os resultados deste trabalho reforçam a importância desta parcela do mercado de trabalho brasileiro, reduzindo também as lacunas dessa área de pesquisa e reitera a importância das variáveis socioeconômicas na determinação da oferta.