Edit: This post originally appeared on my Wordpress blog on September 22, 2009. I present it here in its original form. The R Function of the Day series will focus on describing in plain language how certain R functions work, focusing on sim... [Read more...]

When I use R in Emacs through the ESS package, C-c C-c in a .R buffer will send a “block” of code to the inferior R process for evaluation. This was added just a few years ago, but my fingers are now trained to use that key combination for evaluating ... [Read more...]

Coming from a background writing SQL code directly for “real” RDBMS (Microsoft SQL Server, MySQL, and SQLite), I was initially confused when SAS would give me the following ‘note’ for a simple summary PROC SQL query: 429 proc sql; 430 create table undel_monthly as 431 select 432 year(date) as year, 433 month(date) ... [Read more...]

The R Function of the Day series will focus on describing in plain language how certain R functions work, focusing on simple examples that you can apply to gain insight into your own data. Today, I will discuss the table function. What situation is table useful in? The table function ... [Read more...]

One of the nicer things about many statistics packages is the extremely granular control you get over your graphical output.  But I lack the patience to set dozens of command line flags in R, and I'd rather not power the computer by pumping the mouse trying to set all the ... [Read more...]

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Edit: This post originally appeared on my Wordpress blog on September 20, 2009. I present it here in its original form. The R Function of the Day series will focus on describing in plain language how certain R functions work, focusing on sim... [Read more...]

Edit: This post originally appeared on my Wordpress blog on September 20, 2009. I present it here in its original form. John Tukey's preface to Exploratory Data Analysis begins with a useful rule, "It is important to understand what you can... [Read more...]

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Version 0.1.0 of RInside, my C++ wrapper classes which facilitate embedding R into your own C++ application, has been released and is now an official CRAN package. This release improves on the build process and should work on any sane Unix-alike o... [Read more...]

John Tukey’s preface to Exploratory Data Analysis begins with a useful rule, “It is important to understand what you can do before you learn to measure how well you seem to have done it.” When I decided I wanted to start a blog concentrating on statistics, R, and Emacs, ... [Read more...]

The power of a statistical test is the probability that a null hypothesis will be rejected when the alternative hypothesis is true. In lay terms, power is your ability to refine or "prove" your expectations from the data you collect. The most frequent... [Read more...]

This is tremendously cool. A nice intuitive web-based interface for the lme4 package in R (and you neither need to know R or understand the intricacies of the lme4 package) that gives you pdf output and plots. If you just want to play around and not worry about coding things ... [Read more...]

Yesterday I figured out (together with a friend, Leendert) how to set your R working directory to the path of the current document you're working on in TextWrangler. We developed two scripts: one for setting the working directory of R directly, and one... [Read more...]

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This came up recently on StackOverflow. One of the answers was particularly helpful and I plan to adopt this for my future work. In fact, it is close to what I already do, but is a little more structured. The idea is to break the code into four files, ... [Read more...]

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At this week's R clinic Frank Harrell will unveil the new rms (Regression Modeling Strategies) package that is a replacement for the R Design package.  He will demonstrate the differences with Design, especially related to enhanced graphics for displaying effects in regression models.  Frank will also discuss the implementation of ... [Read more...]

A multiple linear regression (MLR) model that describes a dependent variable y by independent variables x1, x2, ..., xp (p __ 1) is expressed by the equation as follows, where the numbers α and βk (k = 1, 2, ..., p) are the parameter... [Read more...]