Web-site trend analysis with data from Google Analytics

August 25, 2009
By
Web-site trend analysis with data from Google Analytics

This post is a summary of my two previous posts on the trend analysis with the Cox-Stuart test and on simple linear regression. The goal that we propose is to assess the trend in the number of visits received from a site over a long time. I use Google Analytics, because this tool allows us to save...

Read more »

Web-site trend analysis with data from Google Analytics

August 25, 2009
By
Web-site trend analysis with data from Google Analytics

This post is a summary of my two previous posts on the trend analysis with the Cox-Stuart test and on simple linear regression. The goal that we propose is to assess the trend in the number of visits received from a site over a long time. I use Google Analytics, because this tool allows us to save...

Read more »

Applied Spatial Data Analysis with R

August 25, 2009
By
Applied Spatial Data Analysis with R

I have just reviewed the book Applied Spatial Data Analysis with R which has been published in the September2009  issue of the Royal Statistical Society’s Significance magazine. Applied Spatial Data Analysis with R is an accessible text that demonstrates and explains the handling of spatial data using the R Software Platform. The text’s authors have

Read more »

Standardized Velvet Assembly Report

August 25, 2009
By
Standardized Velvet Assembly Report

http://code.google.com/p/standardized-velvet-assembly-report/I finally got my Velvet Assembler report script up on google code. This "program" consists of some short scripts and a Sweave report designed to help Velvet users identify the optimal kmer an...

Read more »

Standardized Velvet Assembly Report

August 25, 2009
By
Standardized Velvet Assembly Report

http://code.google.com/p/standardized-velvet-assembly-report/I finally got my Velvet Assembler report script up on google code. This "program" consists of some short scripts and a Sweave report designed to help Velvet users identify the optimal kmer an...

Read more »

packages and CRANtastic

August 24, 2009
By
packages and CRANtastic

Additional functionality in R is added through packages, which consist of libraries of bundled functions, datasets, examples and help files that can be downloaded from CRAN (the Comprehensive R Archive Network). The function install.packages() or the w...

Read more »

CO2 Emission Trends

August 23, 2009
By
CO2 Emission Trends

“Since 1751 approximately 329 billion tons of carbon have been released to the atmosphere from the consumption of fossil fuels and cement production. Half of these emissions have occurred since the mid 1970s. The 2006 global fossil-fuel carbon emission estimate, 8230 million metric tons of carbon, represents an all-time high and a 3.2% increase

Read more »

R help on StackOverflow

August 23, 2009
By
R help on StackOverflow

Ever since I began using R about ten years ago, the best place to find R help was on the R-help mailing list. But it is time-consuming searching through the archives trying to find something from a long time ago, and there is no way to sort out the good advice from the bad advice.

Read more »

R help on StackOverflow

August 23, 2009
By

Ever since I began using R about ten years ago, the best place to find R help was on the R-help mailing list. But it is time-consuming searching through the archives trying to find something from a long time ago, and there is no way to sort out the goo...

Read more »

R handy for crunching data

August 23, 2009
By
R handy for crunching data

http://www.ibm.com/developerworks/library/l-sc16.html?S_TACT=105AGX52&S_CMP=cn-a-l

Read more »

NpptoR: R in Notepad++

August 22, 2009
By
NpptoR: R in Notepad++

For those who are scared of Emacs: http://sourceforge.net/projects/npptor/

Read more »

Test cointegration with R

Cointegrated pairs of securities are crucial for mean reversion trading portfolio construction, Play with cointegration has several good papers to start with. Should you want to test pairs of securities for cointegration using R, here is an excellent ...

Read more »

No success yet, then more animations…

August 20, 2009
By
No success yet, then more animations…

So I've been here dealing with the installation of a software that Yihui Xie suggested me to change the format of the animations displayed in R, she told me that all I needed to do was to go to http://imagemagick.org to download ImageMagick for my ope...

Read more »

No success yet, then more animations…

August 20, 2009
By
No success yet, then more animations…

So I've been here dealing with the installation of a software that Yihui Xie suggested me to change the format of the animations displayed in R, she told me that all I needed to do was to go to http://imagemagick.org to download ImageMagick for my ope...

Read more »

Simple logistic regression on qualitative dichotomic variables

August 20, 2009
By
Simple logistic regression on qualitative dichotomic variables

In this post we will see briefly how to implement a logistic regression model if you have categorical variables, or qualitative, organized in double entry contingency tables. In this model the dependent variable (Y) and independent variable (X) are both dichotomies (or Bernoullian).In general, the probability that Y = 1 as a function of predictors is:$$P(Y=1|X=x)=\pi(x)=\frac{exp(\beta_0+\beta_1x_1+\cdots +\beta_kx_k)}{1+exp(\beta_0+\beta_1x_1+\cdots +\beta_kx_k)}$$Our goal...

Read more »

Simple logistic regression on qualitative dichotomic variables

August 20, 2009
By
Simple logistic regression on qualitative dichotomic variables

In this post we will see briefly how to implement a logistic regression model if you have categorical variables, or qualitative, organized in double entry contingency tables. In this model the dependent variable (Y) and independent variable (X) are both dichotomies (or Bernoullian).In general, the probability that Y = 1 as a function of predictors is:$$P(Y=1|X=x)=\pi(x)=\frac{exp(\beta_0+\beta_1x_1+\cdots +\beta_kx_k)}{1+exp(\beta_0+\beta_1x_1+\cdots +\beta_kx_k)}$$Our goal...

Read more »

ggplot2 Version of Figures in “Lattice: Multivariate Data Visualization with R” (Part 13)

August 20, 2009
By
ggplot2 Version of Figures in “Lattice: Multivariate Data Visualization with R” (Part 13)

This is the 13th post in a series attempting to recreate the figures in Lattice: Multivariate Data Visualization with R (R code available here) with ggplot2. Previous parts in this series: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11, Part 12. Chapter 14

Read more »

2 Interesting animations…

August 19, 2009
By
2 Interesting animations…

So I haven't had success YET in finding a way to post here the animations, but I thought it would be interesting to show you at least a couple of examples using this software, and I chose 2 pretty interesting ones by Yihui Xie and Xiaoyue Cheng.The fir...

Read more »

2 Interesting animations…

August 19, 2009
By
2 Interesting animations…

So I haven't had success YET in finding a way to post here the animations, but I thought it would be interesting to show you at least a couple of examples using this software, and I chose 2 pretty interesting ones by Yihui Xie and Xiaoyue Cheng.The fir...

Read more »

Have you ever heard about the ‘animation package’?

August 18, 2009
By

Well, I had never heard about it, but this morning I was looking for some information about another package and I found and article about this interesting package at 'The R-Journal' (http://journal.r-project.org/), it was on the Vol. 8/2, October 2008, by Yihui Xie and Xiaoyue Cheng, and it says something like..."The animation package (Xie, 2008) uses graphical andother...

Read more »

Have you ever heard about the ‘animation package’?

August 18, 2009
By

Well, I had never heard about it, but this morning I was looking for some information about another package and I found and article about this interesting package at 'The R-Journal' (http://journal.r-project.org/), it was on the Vol. 8/2, October 2008, by Yihui Xie and Xiaoyue Cheng, and it says something like... "The animation package (Xie, 2008) uses graphical and other...

Read more »

ggplot2 Version of Figures in “Lattice: Multivariate Data Visualization with R” (Part 12)

August 18, 2009
By
ggplot2 Version of Figures in “Lattice: Multivariate Data Visualization with R” (Part 12)

This is the 12th post in a series attempting to recreate the figures in Lattice: Multivariate Data Visualization with R (R code available here) with ggplot2. Previous parts in this series: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11. Chapter 13 – Advanced

Read more »

R Coding Style Guide

August 18, 2009
By

I was sent this R style guide, and think it looks like it might be a good idea. R can be pretty difficult to read, especially someone else's.

Read more »

R Coding Style Guide

August 18, 2009
By

I was sent this R style guide, and think it looks like it might be a good idea. R can be pretty difficult to read, especially someone else's.

Read more »

The density function

August 18, 2009
By
The density function

Today I found such an interesting function called "density", this function computes kernel density estimates, that's why I found it pretty interesting, all you need is:the the data from which the estimate is to be computed the smoothing kernel to be us...

Read more »

The density function

August 18, 2009
By
The density function

Today I found such an interesting function called "density", this function computes kernel density estimates, that's why I found it pretty interesting, all you need is:the the data from which the estimate is to be computed the smoothing kernel to be us...

Read more »

Social Network Analysis Resources for R

August 17, 2009
By
Social Network Analysis Resources for R

Social Network Analysis is an increasingly popular tool for modelling dependence structures between social actors. In my department researchers are developing new models for representing such dependence structures (MELNET). In 2007 I gave a talk on my ...

Read more »

Headless R / X11 and Cygwin/X

August 17, 2009
By

Running R on a Linux server in headless mode (i.e. producing graphics without XWindows running) can be tricky. Some people recommend using a virtual X framebuffer. However, I’ve found that the best approach (at least im my opinion) is to use the ...

Read more »

Potential Loss of Arable Land in the Central San Joaquin Valley, CA

August 17, 2009
By
Potential Loss of Arable Land in the Central San Joaquin Valley, CA

Rapid urban and sub-urban expansion in the San Joaquin Valley have resulted in the loss of millions of acres of prime farmland in the last 100 years. Approximately 11% of class 1 (irrigated) land and 7% of class 2 land have already been paved over in the Fresno-Madera region (first image below). Recent projections in the expansion of urban...

Read more »