Blog Archives

More Readable Code with Pipes in R

July 30, 2014
By
More Readable Code with Pipes in R

Several blog posts have made mention of the 'magrittr' package which allows functional arguments to be passed to functions in a pipes style fashion (David Smith ).This stylistic option has several advantages:  1. Reduced requirements of nested par...

Read more »

Making random draws from an arbitrarily defined pdf

July 23, 2014
By
Making random draws from an arbitrarily defined pdf

I recently found myself in need of a function to sample randomly from an arbitrarily defined probability density function. An excellent post by Quantitations shows how to accomplish this using some of Rs fairly sophisticated functional approximation to...

Read more »

The Rise and Fall of the name Jennifer

July 19, 2014
By
The Rise and Fall of the name Jennifer

A recent fascinating post by Analysis at Large got me interested in naming trends analysis. The original post used Social Security data by state to map out the more frequent names by state. While this sounded interesting it turned out a single name (yo...

Read more »

RStudio Webinar with Hadley Wickham: The Grammar and Graphics of Data Science

July 17, 2014
By
RStudio Webinar with Hadley Wickham: The Grammar and Graphics of Data Science

RStudio has recently announced a series of free webinars open to the public. The first of these seminars is given by Hadley Wickham, Rice University Professor, RStudio Chief Scientist, and general super-star of the R development world. Contributing aut...

Read more »

Item Response Theory and Item Information Exploration

July 10, 2014
By
Item Response Theory and Item Information Exploration

In the following post I will map out some item information functions for item response theory (IRT) models using the common 3 parameter logistic model for binary responses. The model takes three parameters (obviously) which relate to the item features ...

Read more »

Estimating Required Coinage

July 5, 2014
By
Estimating Required Coinage

I would like to code up a simple method of minimizing the number of coins required to give change.  Then I would like see what coins are most likely to be called into usage if change is required from a uniform draw between 1 cent and 499 cents. Exported from Notepad++ # Define denominations to search throughden...

Read more »

7 R Quirks That Will Drive You Nutty

May 5, 2014
By
7 R Quirks That Will Drive You Nutty

7 R Quirks That Will Drive You Nutty StumpedEvery language has its idiosyncrasies. Some “designer”“ type languages have less due to extreme thoughtfulness of language engineers. I suspect Julia for example has many less quirks. However, despite...

Read more »

How to Code Something ‘New’ in R

May 1, 2014
By
How to Code Something ‘New’ in R

Programming New Things I currently have been programming in R for more than half a decade and can now fondly look back on the days when I went on a spring break with Venables' little blue book (now out of print).  Back then I was entertained and wowed by R’s...

Read more »

Three Ways to Format R Code for Blogger

April 30, 2014
By
Three Ways to Format R Code for Blogger

Unformatted CodeIf you are like me originally then you might not think it is worth it to spend the extra energy to format your code.  After all people can just copy what you have and paste it into their preferred editor which will do its own forma...

Read more »

Dave Giles on "MCMC for Econometrics Students"

April 29, 2014
By
Dave Giles on "MCMC for Econometrics Students"

In an excellent four part series of posts in March, Dave Giles introduces Markov Chain Monte Carlo (MCMC) and Gibbs samplers.  In these posts he gives a cogent explanation for the reasoning and mechanics involved in this branch of econometrics/sta...

Read more »