February 2010

Reminder: useR! 2010 abstracts due Monday

February 23, 2010 | 0 Comments

Don't forget, if you're planning to attend the R user conference useR! 2010 and are going to present a talk (and if not, why not?), abstracts are due for submission this coming Monday, March 1. That's also the deadline for early-bird registrations, so if you haven't registered yet, now is the time. ... [Read more...]

Numerical Integration/Differentiation in R: FTIR Spectra

February 23, 2010 | 0 Comments

  Stumbled upon an excellent example of how to perform numerical integration in R. Below is an example of piece-wise linear and spline fits to FTIR data, and the resulting computed area under the curve. With a high density of points, it seems like the linear approximation is most efficient and ...
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Slides from “R Productivity Environment” webinar

February 23, 2010 | 0 Comments

Thanks to everyone who attended for the great turnout at this morning's live webinar, 7 Ways to Increase your R Productivity. I really appreciate all the feedback and questions, seems like a lot of people are interested in a code editing and debugging environment for R. If you missed the webinar ... [Read more...]

Mexico’s Economy

February 22, 2010 | 0 Comments

Yesterday the INEGI released the GDP figures for 2009, and since it was an annus horribilis for Mexico, I thought I'd put up a couple of charts. Looking through the Banco de Información Económica I found two series of historical seasonally adjusted GDP data available: GDP in 1993 pesos going ... [Read more...]

Time Series Calendar Heat Maps Using R

February 22, 2010 | 0 Comments

I came across an interesting blog that showcased Charting time series as calendar heat maps in R . It is based upon a great algorithm created by Paul Bleicher,CMO of Humedica. I'll let you link to the other blog to see more details on the background ...
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A quicky..

February 22, 2010 | 0 Comments

If you’re (and you should) interested in principal components then take a good look at this. The linked post will take you by hand to do everything from scratch. If you’re not in the mood then the dollowing R functions will help you. An example. # Generates sample matrix ... [Read more...]

Sudoku via simulated annealing

February 22, 2010 | 0 Comments

The Sudoku puzzle in this Sunday edition of Le Monde was horrendously difficult, so after spending one hour with only 4 entries filled, I decided to feed it to the simulated annealing R program I wrote while visiting SAMSI last year. The R program reached the exact (and only) solution in ...
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Speeding up R code: A case study

February 22, 2010 | 0 Comments

On his Psychology and Statistics blog, Jeromy Anglim tells how he was analyzing some data from a skill acquisition experiment. Needing to run a custom R function across 1.3 million data points, Jeromy estimated it would take several hours for the computation to complete. So, Jeromy set out to optimise the ... [Read more...]

ggplot2 (qplot) text size

February 22, 2010 | 0 Comments

I'm trying to learn qplot in ggplot2, and I'm having a difficult time adjusting text sizes. Well, difficult doesn't descibe it - I can't do it at all. The manual tells me I can use cex just like in plot, but it's not working... [Read more...]

Time-Space Cloud with R

February 22, 2010 | 0 Comments

Here comes another option to analyze a TimeSpace-Track with R. A lattice cloud plots every recorded trackpoint into a 3d-time-space-cube. As the data (planar point pattern) is marked with the daytime, cluster of everyday routines become visible. Here the direct comparison between a function of density and the time-space-cloud. Code ... [Read more...]

Post hoc analysis for Friedman’s Test (R code)

February 22, 2010 | 0 Comments

My goal in this post is to give an overview of Friedman’s Test and then offer R code to perform post hoc analysis on Friedman’s Test results. (The R function can be downloaded from here) Preface: What is Friedman’s Test Friedman test is a non-parametric randomized block ...
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The R type system

February 21, 2010 | 0 Comments

R is a weird beast. Through it's ancestor the S language, it claims a proud heritage reaching back to Bell Labs in the 1970's when S was created as an interactive wrapper around a set of statistical and numerical subroutines. As a programming language,...
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The truncated Poisson

February 21, 2010 | 0 Comments

A common model for counts data is the Poisson. There are cases however that we only record positive counts, ie there is a truncation of 0. This is the truncated Poisson model. To study this model we only need the total counts and the sample size. This comes from the sufficient ...
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Visual Interpretation of Principal Coordinates (of) Neighbor Matrices (PCNM)

February 21, 2010 | 0 Comments

Principal Coordinates (of) Neighbor Matrices (PCNM) is an interesting algorithm, developed by P. Borcard and P. Legendre at the University of Montreal, for the multi-scale analysis of spatial structure. This algorithm is typically applied to a distance matrix, computed from the coordinates where some environmental data were collected. The resulting "... [Read more...]

Uh!

February 20, 2010 | 0 Comments

Didn't know this... a data 0 2 4 7+ 25 34 12 5 It's becoming clear that I have learned R in the most unstructured way...I always do it in two stages :ashamed: [Read more...]

Design of Experiments – Block Designs

February 20, 2010 | 0 Comments

In many experiments where the investigator is comparing a set of treatments there is the possibility of one or more sources of variability in the experimental measurements that can be accounted for during the design stage of the experimentation. For example we might be investigating four different pieces of machinery ...
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Does a Proclamation of Increased Workout Load Matter?

February 20, 2010 | 0 Comments

I forgot to link this up, but I have a new article (joint with our editor) over at Fantasy Ball Junkie. I run an extremely crude model to see if players who were mentioned in the media as having lost weight, gained muscle, gained speed, got eye surgery...
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