From the help desk: It's all about the sampling

Effective estimation and inference, when the data are collected using complex survey designs, requires estimators that fully account for the sampling design. This article explores, by means of Monte Carlo simulations of the power of simple hypothesis tests, the consequences of parameter estimation and inference when naive estimators are employed with survey data. Copyright 2002 by Stata Corporation.cluster, design, power, strata, svy, svymean, svyset

Response of maize inbred lines to two European corn borer (Ostrinia nubilalis) strains in Canada

Six lignées de maïs-grain (CM47, A619, F2, CM107, CM7 et A654) ont été évaluées en 1986 et 1987 dans quatre localités de l'Ontario et du Québec pour leur résistance à des infestations artificielles de la pyrale du maïs, Ostrinia nubilalis, de la race univoltine et de la première génération de la race bivoltine. Trois critères ont été utilisés: la criblure du feuillage, les dégâts totaux des plantes à la récolte, et le rapport longueur des galeries creusées par les chenilles dans les tiges sur la hauteur des plantes. Des interactions importantes ont été observées pour les critères utilisés entre les années et localités, mais la réaction des lignées de maïs a été plutôt constante. Pour tous les critères, la race univoltine a souvent causé, d'une façon significative, plus de dégâts aux plantes que la race bivoltine. En général, la lignée A619 a démontré le plus de résistance-tolérance tout en conservant une bonne tenue des tiges jusqu'à la récolte. On aurait avantage à utiliser la race univoltine dans les programmes d'amélioration génétique du maïs pour sa résistance à la pyrale.In 1986 and 1987, six maize inbred lines (CM47, A619, F2, CM107, CM7, and A654) were evaluated at four locations across Ontario and Quebec for their resistance to artificially infested univoltine and lst generation bivoltine strains of the European corn borer, Ostrinia nubilalis. Three criteria were used: leaf feeding, total plant damage at harvest and length of tunnels/plant height ratio. Substantial interactions in borer damage measurements were observed between locations and years, but inbred reaction was relatively consistent. For all criteria, the univoltine strain often caused significantly more damage than the bivoltine borer. In general, A619 had the greatest resistance-tolerance with good standability until harvest. Wherever possible, evaluation of genetic resistance in maize germplasm should be conducted using the univoltine borer strain

Survey data analysis in Stata

In this presentation, I cover how to use Stata for survey data analysis assuming a fixed population. We will begin by reviewing the sampling methods used to collect survey data, and how they affect the estimation of totals, ratios, and regression coefficients. We will then cover the three variance estimators implemented in Stata's survey estimation commands. Strata with a single sampling unit, certainty sampling units, subpopulation estimation, and poststratification will be also covered in some detail.

Investigating the effects of factor variables

Stata has a rich set of operators for specifying factor variables in linear and nonlinear regression models. I will show how to test for the effects of factor variables in these models. I will also show how to compare and contrast these effects using linear combinations of the model coefficients.

Unravelling the spectra of stewards and collectors

Non peer reviewe

The Development of Pest Management Strategies for Insect and Plant Diseases in Processing Tomatoes - 2001

A summary of objectives and results related to pest management and plant diseases in processing tomatoes related to fungal disease and seed treatments.Ontario Tomato Research Institut

The Dangers of Conflating Responsible and Responsive Artefact Stewardship with Illicit and illegal collecting

Archaeology and private artefact collecting have complex and inextricably linked histories. Archaeologists have long drawn attention to criminal activity among collectors, but to assume that all private owners of cultural material-and any archaeologists who interact with them-have ill-intent or engage in illegal behaviour can cause as much harm to the archaeological record as the criminal actions themselves.Non peer reviewe

Insect and Plant Disease Control in Tomato Plug Transplants

This report discusses foliar and stem plant disease control strategies and practices related to tomato plug transplants.Ridgetown College, University of Guelp

Damping Off Control in Tomato Plug Plants

This report brings attention to practices that help in the establishment of the seedlings to avoid losses due to damping off disease organisms

Greenhouse Hygiene Protocol

This report discusses the protocol for greenhouse hygiene such as sanitation, green skirting, seed treatment, and protective spraying.Ridgetown College, University of Guelp