Links to slides and talks from useR 2011 - all organized in one page.Read more »
Classification trees are known to be unstable with respect to training data. Recently I have read an article on stability of classification trees by Briand et al. (2009). They propose a quantitative similarity measure between two trees. The method is i...
“Statistics with R” is a great R graphics & stats website. It provides lots of R examples, covering many analytics topics. It is also available as a PDF document to download at the website, as well as the R codes. … Continue reading →
The important criterion for a graph is not simply how fast we can see a result; rather it is whether through the use of the graph we can see something that would have been harder to see otherwise or that could not have been seen at all. – William Cleveland, The Elements of Graphing Data, Related posts:
Happy last month of 2011. I will fly to Sydney to present a paper at the 24th Australasian Finance & Banking Conference on next Thursday, so we may not have a review next week. However, feel free to contact me @a_biao for sharing any useful post. This week's review is highly concentrated on
I was recently asked by a R user about how one could extract the “rule” in a classification/regression tree. The requirement was to obtain the path traced from the root node to the leaf nodes and obtain all the paths or “rules” path.rpart() function in the mvpart package provides this convenience library(mvpart) # Create a
Regression Basicsy= b0 + b1 *X ‘regression line we want to fit’The method of least squares minimizes the squared distance between the line ‘y’ andindividual data observations yi. That is minimize: ∑ ei2 = ∑ (yi - b0 - b1 Xi...
I analyze a lot of experiments and there are many times when I want to quickly look at means and standard errors for each cell (experimental condition), or the same for each cell and individual-level attribute level (e.g., Democrat, Independent, … Continue reading →
Like a lot of other R users I’ve felt the need for sending email from R. I haven’t surveyed CRAN for such a package but looked for the possibility of sending command line email in Windows. Found a nice application called sendEmail that can be found here Below are code snippets in R that will
This post is somewhat marginal to R in that there are several statistical systems that could be used to tackle the problem. Bayesian statistics is one of those topics that I would like to understand better, much better, in fact. … Continue reading →