## predatory but not that smart…

Posted in Statistics with tags , , , , , on May 27, 2018 by xi'an

An email I received earlier this week, quite typical of predatory journals seeking names for their board, but unable to distinguish comments from papers, statistics from mathematical physics, or to spot spelling mistakes:

Dear Christian P. Rober,

Greetings and good day.

I look forward to hearing your positive response. Thank you for your kind consideration.

## [h]it figures

Posted in Books, pictures with tags , , , , , on June 1, 2014 by xi'an

Just a few figures from wordpress about the ‘Og:

• 2,845 posts;
• 1,009,428 views;
• 5,095 tags;
• 1,001 spams in the past 24 hours;
• and… only 5 amazon orders in the past month!

## Valen in Le Monde

Posted in Books, Statistics, University life with tags , , , , , , , , , , on November 21, 2013 by xi'an

Valen Johnson made the headline in Le Monde, last week. (More precisely, to the scientific blog Passeur de Sciences. Thanks, Julien, for the pointer!) With the alarming title of “(A study questions one major tool of the scientific approach). The reason for this French fame is Valen’s recent paper in PNAS, Revised standards for statistical evidence, where he puts forward his uniformly most powerful Bayesian tests (recently discussed on the ‘Og) to argue against the standard 0.05 significance level and in favour of “the 0.005 or 0.001 level of significance.”

“…many statisticians have noted that P values of 0.05 may correspond to Bayes factors that only favor the alternative hypothesis by odds of 3 or 4–1…” V. Johnson, PNAS

While I do plan to discuss the PNAS paper later (and possibly write a comment letter to PNAS with Andrew), I find interesting the way it made the headlines within days of its (early edition) publication: the argument suggesting to replace .05 with .001 to increase the proportion of reproducible studies is both simple and convincing for a scientific journalist. If only the issue with p-values and statistical testing could be that simple… For instance, the above quote from Valen is reproduced as “an [alternative] hypothesis that stands right below the significance level has in truth only 3 to 5 chances to 1 to be true”, the “truth” popping out of nowhere. (If you read French, the 300+ comments on the blog are also worth their weight in jellybeans…)

Posted in Statistics, University life with tags , , , , on June 23, 2010 by xi'an

Following discussions at CREST, we have contributed comments on the following papers

Bernardo, José M. (Universitat de València, Spain)
Integrated objective Bayesian estimation and hypothesis testing. [discussion]

Consonni, Guido (Università di Pavia, Italy)
On moment priors for Bayesian model choice with applications to directed acyclic graphs. [discussion]

Frühwirth-Schnatter, Sylvia (Johannes Kepler Universität Linz, Austria)
Bayesian variable selection for random intercept modeling of Gaussian and non-Gaussian data. [discussion]

Huber, Mark (Claremont McKenna College, USA)
Using TPA for Bayesian inference. [discussion]

Lopes, Hedibert (University of Chicago, USA)
Particle learning for sequential Bayesian computation. [discussion]

Polson, Nicholas (University of Chicago, USA)
Shrink globally, act locally: Sparse Bayesian regularization and prediction. [discussion]

Wilkinson, Darren (University of Newcastle, UK)
Parameter inference for stochastic kinetic models of bacterial gene regulation: a Bayesian approach to systems biology. [discussion]

(with a possible incoming update on Mark Huber’s comments if we manage to get the simulations running in due time).

## LaTeX surprises

Posted in Books, University life with tags , , , , , on January 18, 2010 by xi'an

When compiling the solution manual to “Introducing Monte Carlo Methods with R” into a version with only the odd-numbered exercises, I used a \relax{…} command to comment out the even-numbered solutions. This produced a strange bug when applied to a paragraph that included the lines

\begin{verbatim}
> system.time({for (t in 1:100) y=rmnorm(n=1,var=Sigma)})
user  system elapsed
0.028   0.000   0.028
\end{verbatim}

as somehow the curly bracket } in the group of commands was understood as the end of the \relax command. It took me a while to spot the reason for this bug as I implicitely assumed that anything within the verbatim environment was not understood as a LaTeX command. But the bug was also helpful in pointing out an extra curly bracket } in an R code provided as a solution (within the verbatim environment). While switching between the long and the short versions of the solution manual to “Introducing Monte Carlo Methods with R”, I also found a point I had been seeking for a while, namely that

\begin{comment}
\subsection{Exercise \ref{exo:helpme}}
Test the \verb+help+ command on the functions \verb+seq+,
\verb+sample+, and \verb+order+.
\end{comment}

works out nicely to comment out whole paragraphs once the verbatim package is included. However, if I try to shorten the syntax by defining

\newcommand\become{\begin{comment}}
\newcommand\begone{\end{comment}}

I get a compilation error

Runaway argument?!
File ended while scanning use of \next.
<inserted text>
\par

Strange, isn’t it?!