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| Registros recuperados: 13 | |
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| Hubbell, Bryan J.. |
| The number of insecticide applications made by an apple grower to control an insect infestation is modeled as a geometric random variable. Insecticide efficacy, rate per application, month of treatment, and method of application all have significant impacts on the expected number of applications. The number of applications to control a given insect population is dependent on the probability of achieving successful control with a given application. Results suggest that northeastern growers have the highest and mid-Atlantic growers the lowest probability of controlling an infestation with a given application. Results also indicate that scales require the least and moths the most number of applications. Growers are not responsive to per unit insecticide... |
| Tipo: Journal Article |
Palavras-chave: Apples; Count data; Geometric; Insect control; Pesticides; Crop Production/Industries. |
| Ano: 1997 |
URL: http://purl.umn.edu/15047 |
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| Park, Timothy A.; Florkowski, Wojciech J.. |
| Timely adoption of new varieties is critical to profitable peach production, and peach quality is a primary factor driving adoption. An adoption model for peach varieties is estimated, incorporating grower evaluations of peach quality. The model identifies the impact of farm characteristics such as the farmer's quality preferences, on-farm agronomic and orchard conditions, as well as geographic effects in Georgia peach-growing regions. The relative impact of the key external and internal peach quality attributes on adoption is assessed. Decisions on new varieties are influenced by the age distribution of the orchard, information which can be used in targeting new varieties to growers. |
| Tipo: Journal Article |
Palavras-chave: Count data; Peach variety adoption; Robust standard errors; Crop Production/Industries. |
| Ano: 2003 |
URL: http://purl.umn.edu/30724 |
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| Lohr, Luanne; Park, Timothy A.. |
| We study the demand by organic farmers for technical advice using a quantile regression for the demand of organic farmers for consultations with private information providers. There is substantial heterogeneity in the impact of critical explanatory variables on consultations of organic farmer. Larger farm size has a positive effect on contacts, but the effect is absent for the highest number of consultations. Internet use has a positive marginal effect on visits to private information providers across each quantile, suggesting that expanded efforts to deliver programs through web-based resources are a useful investment for information providers. |
| Tipo: Article |
Palavras-chave: Organic farming; Technical assistance; Quantile regression model; Count data; Internet access; Marketing; C25; Q12; Q13; Q16. |
| Ano: 2012 |
URL: http://purl.umn.edu/123784 |
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| Miranda, Alfonso; Rabe-Hesketh, Sophia. |
| Studying behavior in economics, sociology, and statistics often involves fitting models in which the response variable depends on a dummy variable—also known as a regime-switch variable—or in which the response variable is observed only if a particular selection condition is met. In either case, standard regression techniques deliver inconsistent estimators if unobserved factors that affect the response are correlated with unobserved factors that affect the switching or selection variable. Consistent estimators can be obtained by maximum likelihood estimation of a joint model of the outcome and switching or selection variable. This article describes a “wrapper” program, ssm, that calls gllamm (Rabe-Hesketh, Skrondal, and Pickles, GLLAMM Manual [University... |
| Tipo: Journal Article |
Palavras-chave: Endogenous switching; Sample selection; Binary variable; Count data; Ordinal variable; Probit; Poisson regression; Adaptive quadrature; Gllamm; Wrapper; Ssm; Research Methods/ Statistical Methods. |
| Ano: 2006 |
URL: http://purl.umn.edu/117582 |
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| Registros recuperados: 13 | |
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