Archive for Pratique R

wrong algebra for slice sampler

Posted in Books, Kids, R, Statistics with tags , , , , , , , , , , , , on January 27, 2021 by xi'an

Once more, and thrice alas!, I became aware of a typo in our “Use R!” book through a question on X validated from a reader unable to reproduce the slice of a basic 2D slice sampler for a logistic regression with coefficients (a,b). Indeed, our slice reads as the incorrect set (missing the i=1,…,n)

\left\{ (a,b): y_i(a+bx_i) > \log \frac{u_i}{1-u_i} \right\}

when it should have been

\bigcap_{i=1} \left\{ (a,b)\,:\ (-1)^{y_i}(a+bx_i) > \log\frac{u_i}{1-u_i} \right\}

which is the version I found in my LaTeX file. So I do not know what happened (unless I corrected the LaTeX file at a later date and cannot remember it, but the latest chance on the file reads October 2011…). Fortunately, the resulting slices in a and b and the following R code remain correct. Unfortunately, both French and Japanese translations reproduce the mistake…

Méthodes de Monte-Carlo avec R

Posted in Books, Kids, R, Statistics, University life with tags , , , , , on December 3, 2010 by xi'an

The translation of the book Introducing Monte Carlo Methods with R is close to being completed. The copy-editing and page-setting are done, I have received the cover proposal and am happy with it, so it should now go to production and be ready by early January, (earlier than the tentative end of February indicated on amazon) maybe in time for my R class students to get it before the exam. Thanks to the efforts of Pierre-André Cornillon and Eric Matzner (from the Université de Haute-Bretagne in Rennes), the move from the Use R! series format to the Pratique R series format was done seamlessly and effortlessly for me. (Again, thanks to the traductors who did produce their translations in sometimes less than a month!) I am curious to see how much of a market there is for the French translation… The Japanese translation is scheduled for August 2011 at the very least, but I am obviously not involved at all in this translation!

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