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Hedging the Return on Equity and Firm Profit: Evidence from Canadian Oil and Gas CompaniesZhu, Jiachi 22 August 2012 (has links)
In this thesis, we analyse the relationship between the hedging activities and return on equity, and the relationship between profit on hedging and other factors. Fully conditional specification is used to impute the missing values. Instrumental variable estimation and finite mixture of regression models are then used to predict the return on equity and hedging gain. We find the instrumental variable estimation is better than the OLS estimation to deal with the hedging data since it eliminates the endogeneity. By finite mixture of regression models, we show that different firms have different hedging strategies, which cause different profits in hedging. We also find the companies with large total assets prefer to hedge.
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Misturas de modelos de regressão linear com erros nas variáveis usando misturas de escala da normal assimétricaMonteiro, Renata Evangelista, 92-99124-4468 12 March 2018 (has links)
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Previous issue date: 2018-03-12 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The traditional estimation of mixture regression models is based on the assumption
of normality of component errors and thus is sensitive to outliers, heavy-tailed and/or
asymmetric errors. Another drawback is that, in general, the analysis is restricted to
directly observed predictors.
We present a proposal to deal with these issues simultaneously in the context of
mixture regression by extending the classic normal model by assuming that, for each
mixture component, the random errors and the covariates jointly follow a scale mixture of
skew-normal distributions. It is also assumed that the covariates are observed with error.
An MCMC-type algorithm to perform Bayesian inference is developed and, in
order to show the efficacy of the proposed methods, simulated and real data sets are
analyzed. / A estimação tradicional em mistura de modelos de regressão é baseada na suposição
de normalidade para os erros aleatórios, sendo assim, sensível a outliers, caudas
pesadas e erros assimétricos. Outra desvantagem é que, em geral, a análise é restrita a
preditores que são observados diretamente.
Apresentamos uma proposta para lidar com estas questões simultaneamente no
contexto de mistura de regressões estendendo o modelo normal clássico. Assumimos
que, conjuntamente e em cada componente da mistura, os erros aleatórios e as covariáveis
seguem uma mistura de escala da distribuição normal assimétrica. Além disso, é feita a
suposição de que as covariáveis são observadas com erro aditivo.
Um algorítmo do tipo MCMC foi desenvolvido para realizar inferência Bayesiana.
A eficácia do modelo proposto é verificada via análises de dados simulados e reais.
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