Three approaches to understanding 3-way anova interactions will be presented: 1) a conceptual approach, 2) an anova approach and 3) a regression approach using dummy coding. The three approaches are illustrated through the use of a synthetic dataset with a significant 3-way interaction.

I research the market efficiency of the German 6/49 parimutuel lottery game using Stata. To this end, I investigate the existence of profit opportunities for particularly unpopular combinations of numbers (Papachristou and Karamanis (1998)), employing the covariates proposed by Henze and Riedwyl...

A Stata program will be presented for improved quality control of econometric models. It is well known that reported econometric results often have unknown reliability because of selective reporting by the researcher. In particular, t-statistics are often uninformative or misleading when...

Stata's matrix language, Mata, highlighted in Bill Gould's Mata Matters columns in the Stata Journal, is very useful and powerful in its interactive mode. Stata users who write do-files or ado-files should gain an understanding of the Stata-Mata interface: how Mata may be called upon to do one...

Literature on causal inference has emphasized the average causal effect, defined as the mean difference in potential outcomes under different treatment conditions. We consider marginal regression models that describe how causal effects vary in relation to covariates. To estimate parameters, we...

In the past decade, many statistical methods have been proposed for the analysis of case–control genetic data with an emphasis on haplotype-based disease association studies. Most of the methodology has concentrated on the estimation of genetic (haplotype) main effects. Most methods accounted...

Through the use of user-written programs, primarily mim (Carlin, Galati, and Royston, 2008), Stata users can analyze multiply imputed (MI) datasets. Among other capabilities, mim allows the user to estimate a range of regression models and to perform a multi-parameter hypothesis tests after...

Analyzing survey data is different from analyzing data generated by experiments in several important ways. These differences will be discussed using the NHANES III adult data set as an example. Topics will include specifying the survey elements, analysis of subpopulations, model diagnostics and...

Stata is a very good tool to analyze survey data. It is able to consider many important aspects of complex survey design and the availability of alternative variance estimation methods. Through the use of matrix and macro language it also allows the user to store and manage output results...

This presentation focuses on predicted probabilities for multilevel models for dichotomous or ordinal responses. In a three-level model, for instance with patients nested in doctors nested in hospitals, predictions for patients could be for new or existing doctors and, in the latter case, for...