April 2013

Le Monde puzzle [#817]

April 18, 2013 | xi'an

The weekly Le Monde puzzle is (again) a permutation problem that can be rephrased as follows: Find where denotes the set of permutations on {0,…,10} and is defined modulo 11 [to turn {0,...,10} into a torus]. Same question for and for This is rather straightforward to code if one adopts a brute-force approach:: (...
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Debugging Tools in R with Michael Hannon

April 18, 2013 | Noam Ross

Today at Davis R Users’ Group, Michael Hannon gave a great talk on how to use R’s native debugging functions. Here are his notes and code. Introduction This is a discussion of debugging techniques in R. It is based on a paper by Roger Peng, now at Johns Hopkins ... [Read more...]

MLB Pitcher Values

April 18, 2013 | pssguy

Not the start Blue Jays fans were looking for. With a 6-9 record at the time of publication they already trail Boston (led by reviled ex-BJ manager, John Farrell) by 4.5 games. The batting has been particularly anemic but the pitching – particularly the starting rotation – has also been a concern I ... [Read more...]

Cut Dates Into Quarters

April 18, 2013 | Jason Bryer

Frequently I need to recode a date column to quarters. For example, at Excelsior College we have continuous enrollment so we report new enrollments per quarter. To complicate things a bit, our fiscal year starts in July so that July, August, and September represent the first quarter, January, February, and ... [Read more...]

CrossFit weights: gender matters less than you’d think

April 17, 2013 | Mark T Patterson

Exploring Gaussian Mixture Models Exploring Gaussian Mixture Models This week in the Empirical Research Methods course, we've been talking a lot about measurement error. The idea of having some latent variable of interest, coupled with 'flawed' measures reminded me of a section of Cosma's course I really enjoyed, but haven't ... [Read more...]

Banging on the JGBs

April 17, 2013 | klr

Since I have not posted in quite a while, I wanted to let everyone know that I am still alive and kicking.  The resurrection of excitement (opportunity) in the markets, quarterly reporting cycle, and the overwhelming number of unbelievable R/javascript releases have kept me from writing something good enough ... [Read more...]

More reasons not to use Excel for modeling

April 17, 2013 | David Smith

As if the London Whale nearly bankrupting Chase Bank wasn't lesson enough, we now hear that an Excel error impacted the conclusions of a major economics paper that influenced the recent austerity policies in the US, UK and elsewhere. Matt Frost says enough is enough, and implores to everyone to ... [Read more...]

Mind Reading… What are our customers thinking?

April 17, 2013 | mhornick

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Overhauling analytics processes is becoming a recurring theme among customers. A major telecommunication provider recently embarked on overhauling their analytics process for customer surveys. They had three broad technical goals: Provide an agile environment that empowers business analysts to test hypotheses based ... [Read more...]

ggplot dodged vs faceted bar chart

April 17, 2013 | Cory Nissen

I've been bowling once per year at a charity event for the last few years and have kept track of the outcomes to share my group. I used ggplot2 to create a bar chart for the scores. Below are two graphs, one is dodged, the other is faceted. There's no ...
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Interview with a forced convert from Matlab to R

April 17, 2013 | Patrick Burns

Here is an interview with Ron Hochreiter, Assistant Professor at WU Vienna University Economics and Business. In 25 words or less tell us what you do (using German words is cheating). I consider myself as a data scientist (teaching and research) with roots in Mathematical Programming, i.e. Optimization under Uncertainty (... [Read more...]

big geo-data visualisations

April 17, 2013 | Rolf Fredheim

Spotting international conflict is very easy with the GDELT data set, combined with ggplot and R. The simple gif above shows snapshots of Russian/Soviet activity from January 1980 and January 2000. I think it also illustrates how Russia nowadays looks more to the east and the South than during the Cold ... [Read more...]

R Color Reference Sheet

April 16, 2013 | Michał

R has a built-in collection of 657 colors that you can use in plotting functions by using color names. There are also various facilities to select color sequences more systematically: Color palettes and ramps available in packages RColorBrewer and colorRamps. R base functions colorRamp and colorRampPalette that you can use to ... [Read more...]

Looking Ahead: Revolution R Enterprise Release 7

April 16, 2013 | Thomas W DInsmore

by Thomas Dinsmore Revolution R Enterprise Release 6.2 goes live next week, so naturally our development team is thinking ahead to Release 7, which we plan to release later this year. Some of those enhancements are hush-hush, and we can't talk about them yet. But one of the most important enhancements we've ... [Read more...]

Flotsam 11: mostly on books

April 16, 2013 | Luis

‘No estaba muerto, andaba the parranda’† as the song says. Although rather than partying it mostly has been reading, taking pictures and trying to learn how to record sounds. Here there are some things I’ve come across lately. I can’t remember if I’ve recommended Matloff’s The ... [Read more...]
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