Very. If you have 10 possible independent regressors, and none of which matter, you have a good chance to find at least one is important. A good chance being 40%: prob(one or more looks important) = 1 – prob(non looks … Continue reading →
726 search results for "Latex"
Playing cards in Vegas?
In a previous post, a few weeks ago, I mentioned that I will be in Las Vegas by the end of July. And I took the opportunity to write a post on roulette(s). Since some colleagues told me I should take some time to play poker there, I guess I have to understand how to play poker… so I...
Analyzing a simple experiment with heterogeneous variances using asreml, MCMCglmm and SAS
I was working with a small experiment which includes families from two Eucalyptus species and thought it would be nice to code a first analysis using alternative approaches. The experiment is a randomized complete block design, with species as fixed … Continue reading →
Forecasting annual totals from monthly data
This question was posed on crossvalidated.com: I have a monthly time series (for 2009–2012 non-stationary, with seasonality). I can use ARIMA (or ETS) to obtain point and interval forecasts for each month of 2013, but I am interested in forecasting the total for the whole year, including prediction intervals. Is there an easy way in R to obtain interval...
Animations Understood
When I first saw a graphic made from Yihui’s animation package (Xie, 2012) I was amazed at the magic and thought “I could never do that”. Passage of time… One night I found myself bored and as usual avoiding work. … Continue reading →
AIC & BIC vs. Crossvalidation
Model selection is a process of seeking the model in a set of candidate models that gives the best balance between model fit and complexity (Burnham & Anderson 2002). I have always used AIC for that. But you can also…
Veterinary Epidemiologic Research: Count and Rate Data – Zero Counts
Continuing on the examples from the book Veterinary Epidemiologic Research, we look today at modelling count when the count of zeros may be higher or lower than expected from a Poisson or negative binomial distribution. When there’s an excess of zero counts, you can fit either a zero-inflated model or a hurdle model. If zero 
LaTeX in R graphs
A nice post was recently published on the rsnippets blog, about the tikzDevice R package. This package is – indeed – awesome. Even if it has been removed from the CRAN website. Of course, it can be download from the archive folder, on http://cran.r-project.org/…, but also (for a more recent version) on http://download.r-forge.r-project.org/…. But first, it is necessary to install...
Animation, from R to LaTeX
Just a short post, to share some codes used to generate animated graphs, with R. Assume that we would like to illustrate the law of large number, and the convergence of the average value from binomial sample. We can generate samples using > n=200 > k=1000 > set.seed(1) > X=matrix(sample(0:1,size=n*k,replace=TRUE),n,k) Each row will be a trajectory of heads and...
All you need is text – Markdown (via pandoc) for academia
Many students struggle to find an adequte format for their thesis. Ironically the advent of “modern” WYSIWYG programms seems to make it harder to consistently format a text. While learning LaTeX may be a bit too much to ask for, markdown is a very minimal language that together with pandoc affords all typesetting needs for
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
