Matthew Sigal

Recently Published

Interactions for Continuous Variables via Multiple Regression with R
A short examination of constructing interactions terms for continuous variables for multiple regression models in R.
General Approaches with Computerized Adaptive Testing
Models for nominal/ordinal item level data.
Factorial Repeated Measures ANOVA
Quick overview of converting from wide format data to long format for a 3x3 repeated measures dataset.
Playing with coordinates in ggplot2.
A nice feature of `ggplot2` is the ability to apply differing coordinate systems. While most often graphics are expressed on Cartesian coordinates, sometimes it is interesting to use different bases. In this gist, I show a few applications of polar coordinates.
Tranformations in ggplot2
A quick description of how transforming different elements in a ggplot2 object produces differing results.
Highcharts.js via rCharts
Relationship between Smoking and Exercise.