Author Archives: Durwood Marshall

Mixed Model framework for GeneArray analysis

An excellent recent article caught my attention that solves in a unified manner a class of gene array analysis problems using the work horse methodology of statistical Mixed Models. The approach taken is presented for a two group time course … Continue reading

Posted in Uncategorized | Leave a comment

Epi – Statistic tools for Epidemiology

Epi has been around for a long time, starting back in the days of DOS! Over the years Epi has matured into a suite of tools(Pepi) that has the fields of public health and epidemiology as its focus. WINPEPI software … Continue reading

Posted in Uncategorized | Leave a comment

MCA – a thing of the past?

All pair-wise Multiple Comparisons(MCA) is a well known collection of procedures for the stochastic ordering of means; which is a common research task. Classical methods rely on the assumption that the null hypothesis is true. Modern alternatives can be found … Continue reading

Posted in Uncategorized | Leave a comment

An improved Spatial Scan Statistic

Spatial scan statistics have been an important class of tools for cluster detection in spatial data. These are often used in support of surveillance and detection activities in public health and other fields. A common limitation of popular spatial scan … Continue reading

Posted in Uncategorized | Leave a comment

mixAK: New data clustering options

Cluster Analysis(and other tools) are often deployed to investigate structure(clustering) in multidimensional data sets. One approach to model such data is the Gaussian mixture model. mixAK is a new R package for Bayesian estimation of multivariate normal mixtures allowing for … Continue reading

Posted in Uncategorized | Leave a comment

Survey weights and new ANES suggestions

Many large surveys are structured as complex sample designs that reflect various stratification considerations. Statistics calculated from such designs must be weighted to reflect the general population of interest. A clear discussion and set of recommendations by four prominent researchers … Continue reading

Posted in Uncategorized | Leave a comment

Areal and point source spatial data models

Researchers using spatial data are often faced with a mix of data obtained from several levels of scale, aggregation and point reference data. Classical geospatial regressions do not deal with this mix very well, and standard ordinary regressions even worst. … Continue reading

Posted in Uncategorized | Leave a comment

Spss resources

Spss software has an extensive tutorial built into its product and most first time users will benefit from using it. Additional Spss resources can be found here.

Posted in Uncategorized | Leave a comment

R available on Tufts Linux Cluster

Elsewhere on this Blog I mention various bits and pieces of R software. Now that the fall semester is upon us, we have added many new R BioInformatic packages to the baseline R installation on our research linux cluster. This … Continue reading

Posted in Uncategorized | Leave a comment

Bayes Software…the next big effort

Historically, Bayesian solutions were computed as needed in formal languages(Fortran, C,java,etc…) and later in high level solutions like Matlab,Gauss,SAS/IML and others. Then Winbugs came along and offered a higher level interface, similar to what Matlab did for linear algebra syntax … Continue reading

Posted in Uncategorized | Leave a comment