I started using Git some time ago, but mostly for local work files. Today, I finally sync’ed up a repository for loss reserving analysis. It may be found here: https://github.com/PirateGrunt/MRMR MRMR stands for Multivariate Regression Model for Reserves. When pronounced “Mister Mister” it also sounds ... [Read more...]

Using R snippets written by other developers can be unendingly maddening.  There are a variety of reasons for this, most of which boil down to a simple issue: most code is written such that a system must be configured in … Continue reading → [Read more...]

Just like a lot of political science departments, here at Rice a group of faculty and students meet each week to discuss new research in political methodology. This week, we read a new symposium in Political Analysis about the pre-registration of studies in political science. To briefly summarize, several researchers ... [Read more...]

Here is a spot of code to create a series of small multiples for comparing return distributions. You may have spotted this in a presentation I posted about earlier, but I’ve been using it here and there and am finally satisfied that it is a generally useful view, so ... [Read more...]

When plotting, I am constantly defaulting to the "main" colors in R - In other words, the colors that one can quickly call by number (1="black", 2="red", 3="green", 4="blue", ... etc.) . In my opinion, these colors do not lend themselves well to compelling graphics. I imagine this is the reason for ... [Read more...]

[Read more...]

[Read more...]

I was interested in modeling the relationship between the power and sample size, while holding the significance level constant (p = 0.05) , for the common two-sample t-Test. Luckily R has great support for power analysis and I found the function I was looking for in the package pwr. To calculate the power ... [Read more...]

In case you missed them, here are some articles from December of particular interest to R users. The blog is.R ran an excellent series of R tips and applications in December, with posts including working with Stata files, working with graphs and networks, and text analysis. Kohske Takahashi provides ... [Read more...]

[Read more...]

Gaston Sanchez’s post on R-Bloggers inspired me to waste a bit of time. He wanted to replicate the Google Charts widget to make gauges. I modified his code (below) in some minor ways and made a function out of it so you can alter the look and feel of ... [Read more...]

The Gini coefficient is a measure of the inequality of a distribution, most commonly used to compare inequality in income or wealth among countries.Let's first generate some random data to analyze. You can download my random data or use the code below ... [Read more...]

It has been several month since my last post, partially due to the fact that my laptop was lost and several deadlines was approaching. Fortunately I will be returning to Taiwan and get a new laptop within a week, and will be updating regularly again.This post will provide a ... [Read more...]

Answer:  The variance-covariance matrix containing all the MaxDiff scores is not invertible.  R tells you that, either with an error message or a warning.  SPSS, at least earlier versions still in use, runs the factor analysis witho... [Read more...]

At Davis R Users’ Group yesteray, Steve Culman gave us an introduction to the plyr package and how to use it to manipulate data. Here’s his presentation, and the accompanying demonstration script: Steve’s talk is based on this paper by Hadley Wickham in the Journal of Statistical Software. ... [Read more...]

Hi, if you like me work in medical research, you have to plot the results of multiple logistic regressions every once in a while. As I have not yet found a great solution to make these plots I have put together the following short skript. Do not expect too much, ... [Read more...]

There are two online courses starting soon on Coursera, which are free to register. 1. Data Analysis (with R) It is a 8-week online course starting on Jan 22nd 2013 . This course is an applied statistics course focusing on … Continue reading → [Read more...]

[Read more...]

Finally, the fog lasting for days went away this morning and the sun comes out. It’s a lovely winter day. After taking a walk after lunch, I feel like doing some math. So, here comes the 25th Euler problem. The … Continue reading → [Read more...]

In the last post, Examples of Current Major Market Clusters, we looked at clustering Major Markets into 4 groups based on their correlations in 2012. Today, I want to continue with clustering theme and discuss methods of selecting number of clusters. I will look at the following methods of selecting optimal number ... [Read more...]