The feed-forward neural network is a very powerful classification model in the machine learning content. Since the goodness-of-fit of a neural network is majorly dominated by the model complexity, it is very tempting for a modeler to over-parameterize the neural network by using too many hidden layers or/and hidden ... [Read more...]

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Today, I want to demonstrate how easy it is to create a seasonality analysis study and produce a sample summary report. As an example study, I will use S&P Annual Performance After a Big January post by Avondale Asset Management. The first step is to load historical prices and ... [Read more...]

A good three weeks ago, we introduced the Rcpp Gallery. While this is a joint effort by several of us on the Rcpp team, the backend was conceived and implemented entirely by JJ who also bootstrapped it with same first content, drawing on posts by Ha... [Read more...]

A good three weeks ago, we introduced the Rcpp Gallery. While this is a joint effort by several of us on the Rcpp team, the backend was conceived and implemented entirely by JJ who also bootstrapped it with same first content, drawing on posts by Ha... [Read more...]

[This article was first published on NIR-Quimiometria, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your [Read more...]

Summary: Two methods for hierarchical clustering are introduced: (i) dynamic tree cut; and (ii) dynamic hybrid cut. Dynamic tree cut is a top-down algorithm that relies solely on the dendrogram. The algorithm implements an adaptive, iterative process of cluster decomposition … Continue reading → [Read more...]

In this post we will talk about the R package “arcdiagram” for plotting pretty arc diagrams like the one below: Arc Diagrams An arc diagram is a graphical display to visualize graphs or networks in a one-dimensional layout. The main idea is to display nodes along a single axis, while ... [Read more...]

Mirai Solutions GmbH (http://www.mirai-solutions.com) is very pleased to announce the release of XLConnect 0.2-4, which is available from CRAN. This newest release comes along with a number of new features: Ability to read cached cell values. There is a new … Continue reading → [Read more...]

That is what I read the other day. For calculation of descriptive statistics, values below the LLOQ (lower limit of quantification)  were set to.... Then I wondered, wasn't there a trick in JAGS to incorporate the presence of missing data while es... [Read more...]

After 8 years of using R, today I finally become a contributor to the community and released my first package, FAOSTAT.The package is designed to provide user with direct access to the FAOSTAT data base via R and to support the open data and methodology philosophy used in the Statistical ... [Read more...]

Using R and ggplot2 to draw a scatterplot with the two marginal boxplotsDrawing a scatterplot with the marginal boxplots (or marginal histograms or marginal density plots) has always been a bit tricky (well for me anyway). The approach I take here is, first, to draw the three separate plots using ... [Read more...]

Following my last post about the maize network, although interesting but is not very informative. What we are going to do today is to contrast the maize network with the wine trade network.The choice why we have chose wine will become clear after the network and the analysis. Lets ... [Read more...]

With only 24 hours remaining in the 2012 NFL season, this is a good time to review how the league's QBs performed during the regular season using performance data from KFFL and the heat mapping capabilities of R. #scale data to mean=0, sd=1 and convert to matrix QBscaled [Read more...]

A big problem in reproducible research is that software changes. The code you used to do a piece of research may depend on a specific version of software that has since been changed. This is an annoying problem in R because install.packages only installs the most recent version of ... [Read more...]

Or, The 2010 Mariners: How Bad Were They?In earlier posts, I used the statistical software R to plot the trends in league average run scoring since 1901. This was the first step to answering other questions I had on my mind:How poor was the offensive performance of the 2010 Seattle Mariners?... [Read more...]

I spent a portion of today trying to convince a colleague that there are times when the data.table package is faster than traditional methods in R. It took a few of the tests below to prove the point. Generate a data.frame of characters and numbers for easy plotting. {{... [Read more...]

Consider the following time series, What does it look like ? I know, this is a stupid game, but I keep using it in my time series courses. It does look like a random walk, doesn’t it ? If we use Philipps-Perron test, yes, it does, __ PP.test(x) Phillips-Perron Unit ... [Read more...]

Another site pops up with open code for analyzing public survey data: http://www.asdfree.com/ It will be interesting to see whether this gets used by the general public--given the growing trend of data journalism and so forth--versus academics. It is... [Read more...]

I think you’ve noticed by now that a normal interactive R session is quite messy. If you don’t believe me, try playing around for a while and then give the history() command, which will show you the commands you’ve typed. If you’re anything like me, a ... [Read more...]