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(Unsurprisingly) users default to the defaults

2012-09-19 / Luis

Oddities tend to jump out when one uses software in a daily basis. The situation is even clearer when using software for teaching: many more people looking at it with fresh eyes.

Let’s say that we are fitting a simple linear model and we use the summary function, then POW! i- one gets all sorts of stars next to each of the coefficients and ii- some tiny p-values with lots of digits. Since immemorial times (childcare, at least) we got star stickers when doing a good job and here we have R doing the same. It is possible to remove the stars, I know, but the default is the subject of this post.
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Gratuitous picture: looking for peace in Japan (Photo: Luis).

Mid-September flotsam

2012-09-14 / Luis

This is one of those times of the year: struggling to keep the head above the water, roughly one month before the last lecture of the semester. On top trying to squeeze trips, meetings and presentations in between while dealing with man flu.

Creating a list of introductory-level Bayesian blogs. Some suggestions in the comments: Probably Overthinking It, Maximum Entropy & Deus Dia Pente.
Materials for Statistical Modelling in Stata. HT: Christophe Lalanne.
That damned R-squared! understanding through simulation by Arthur Charpentier.
Strange headlines: ‘Livestock Improvement Corporation offers semen credit in wake of ‘hairy calves’ genetic defect’. HT: Mem Sommerville.
Attention Deficit Disorder sufferers have moved, at least for a while, from talking about Julia to talking about Stan.
I bought a copy of Wes McKinney’s Python for Data Analysis. Worth the price.

Suicide statistics and the Christchurch earthquake

2012-09-06 / Luis

Suicide is a tragic and complex problem. This week New Zealand’s Chief Coroner released its annual statistics on suicide, which come with several tables and figures. One of those figures refers to monthly suicides in the Christchurch region (where I live) and comes with an interesting comment:

Suicides in the Christchurch region (Timaru to Kaikoura) have risen from 67 (2010/11) to 81 (2011/12). The average number of suicides per year for this region over the past four years is 74. The figure of 67 deaths last year reflected the drop in suicides post-earthquake. The phenomenon of a drop in the suicide rate after a large scale crisis event, such as a natural disaster, has been observed elsewhere. [my emphasis]

Gratuitous picture: horse race in the beach (Photo: Luis).

m x n matrix with randomly assigned 0/1

2012-08-29 / Luis

Today Scott Chamberlain tweeted asking for a better/faster solution to building an m x n matrix with randomly assigned 0/1. He already had a working version:

r <- 1000
c <- 1000
m0 <- matrix(0, r, c)
apply(m0, c(1,2), function(x) sample(c(0,1),1))

Trust me

2012-08-24 / Luis

This picture reminded me of The Oatmeal’s How to tell if your cat is plotting to kill you.

Palimpsest

(Unsurprisingly) users default to the defaults

Mid-September flotsam

Suicide statistics and the Christchurch earthquake

m x n matrix with randomly assigned 0/1

Trust me