Chutes & ladders: How long is this going to take?

May 17, 2013
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Chutes & ladders: How long is this going to take?

I was playing Chutes & Ladders with my four-year-old daughter yesterday, and I thought, “How long is this going to take?” I saw an interesting mathematical analysis of the game a few years ago, but it seems to be offline, though you can read it via the wayback machine. But that didn’t answer my specific

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Which Torontonians Want a Casino? Survey Analysis Part 2

May 17, 2013
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Which Torontonians Want a Casino?  Survey Analysis Part 2

In my last post I said that I would try to investigate the question of who actually does want a casino, and whether place of residence is a factor in where they want the casino to be built.  So, here … Continue reading →

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R 3.0.1 released

May 17, 2013
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The R core group has quickly followed up with a patch to R version 3. Announced yesterday, R 3.0.1 (code name: "Good Sport") improves serialization performance with big objects, improves reliability for parallel programming and fixes a few minor bugs. (You can find the complete list of changes in the NEWS file.) The source distribution and Windows and Linux...

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Revolution Newsletter: May 2013

May 17, 2013
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The most recent edition of the Revolution Newsletter is out. The news section is below, and you can read the full May edition (with highlights from this blog and community events) online. You can subscribe to the Revolution Newsletter to get it monthly via email. Gaming Analytics FTW! Join us on 13Jun13 at 10:00 AM PDT for our webinar...

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Strategic Zombie Simulation – Animation

May 17, 2013
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Strategic Zombie Simulation – Animation

# Escape Zombie Land! # This is a simulation an escape from a hot zombie zone. It freezes and gives an error if you get get killed so you had best not. You attempt to navigate the zone by constructing waypoints. # This is not a very clean s...

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Innovation Will Never Be At The Push Of A Button

May 17, 2013
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@randyzwitch @benjamingaines @usujason I am envisioning the data science equivalent of an autonomous vehicle pileup. — Todd Belcher (@toddmetrics) May 16, 2013   Recently, I’ve been getting my blood pressure up reading (marketing) articles about “big data” and “data science”.  What saddens me about the whole discussion is that there is the underlying premise that Innovation Will Never...

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Preferential attachment applied to frequency of accessing a variable

May 17, 2013
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Preferential attachment applied to frequency of accessing a variable

If, when writing code for a function, up to the current point in the code distinct local variables have been accessed for reading times (), will the next read access be from a previously unread local variable and if not what is the likelihood of choosing each of the distinct variables (global variables are ignored

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Analyzing a simple experiment with heterogeneous variances using asreml, MCMCglmm and SAS

May 17, 2013
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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 effect and family and block as a random effects, while the response variable is growth

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Finding patterns in time series using regular expressions

May 17, 2013
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Finding patterns in time series using regular expressions

Regular expressions are a fantastic tool when you’re looking for patterns in time series. I wish I’d realised that sooner. Here’s a timely example: traditionally, when you have two successive quarters of negative GDP growth, you’re in recession. We have a quarterly GDP time series for Australia, and we want to know how many recessions

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Analyze More, Program Less: A Webinar about Using SciDB for Computational Finance

May 16, 2013
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Paradigm4 presents a webinar about using SciDB for scalable financial analytics. You’ll see how SciDB reaches Big Data scale without forcing you to become a computer scientist—no mapping, no reducing, no concocting parallel algorithms by hand. The webinar will also demonstrate SciDB-R, an R package that lets you remain an R programmer while enjoying the scalable

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Social Network Analysis at New Frontiers in Computing 2013

May 16, 2013
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Social Network Analysis at New Frontiers in Computing 2013

by Joseph Rickert This past Saturday, the New Frontiers in Computing Conference (NFIC 2013), held at Stanford University, explored the theme: Social Network Analysis: It’s Who You Know. The speakers were a well-chosen, eclectic lot who covered a remarkable array of issues in less than a full day. Ian Hersey, former CTO of Attensity spoke on Lessons from Large-Scale...

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A function for comparing groups on a set of variables

May 16, 2013
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I'm often in the position of needing to compare groups of either items or participants on some set of variables. For example, I might want to compare recognition of words that differ on some measure of lexical neighborhood density but are matched on wo...

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Using RcppProgress to control the long computations in C++

May 16, 2013
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Using RcppProgress to control the long computations in C++

Usually you write c++ code with R when you want to speedup some calculations. Depending on the parameters, and especially during the development, it is difficult to anticipate the execution time of your computation, so that you do not know if you have to wait for 1 minute or hours. RcppProgress is a tool to help you monitor the...

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Statistics vs Data Science vs BI

May 15, 2013
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Statistics vs Data Science vs BI

As someone who trained as a statistician, I've always struggled with that title. I love the rigor and insight that Statistics brings to data analysis, but let's face it: Statistics — the name — has always had a bit of a branding problem. Telling someone I was a statistician was more likely to conjure up images of me counting...

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Even More JGB Yield Charts with R lattice

May 15, 2013
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Even More JGB Yield Charts with R lattice

See the last post for all the details. I just could not help creating a couple more. Variations on Favorite Plot - Time Series Line of JGB Yields by Maturity p2 <- xyplot(value ~ date | indexname, data = jgb.melt, type = "l", layout = c(length(unique(jgb.melt$indexname)), ...

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Exponential Cache Behavior

May 15, 2013
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Exponential Cache Behavior

Guerrilla alumnus Gary Little observed certain fixed-point behavior in simulations where disk IO blocks are updated randomly in a fixed size cache. For his python simulation with 10 million entries (corresponding to an allocation of about 400 MB of memory) the following results were obtained: Hit ratio (i.e., occupied) = 0.3676748 Miss ratio...

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R code for generating multi-site stochastic precipitation

In water resource management, climate change, hydrology and related disciplines long time series of precipitation/rainfall data is required. Since historical records are relatively short, typically 50 years or less, mathematical/statistical models are ...

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Automated Archival and Visual Analysis of Tweets Mentioning #bog13, Bioinformatics, #rstats, and Others

May 15, 2013
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Automated Archival and Visual Analysis of Tweets Mentioning #bog13, Bioinformatics, #rstats, and Others

Automatically Archiving Twitter ResultsEver since Twitter gamed its own API and killed off great services like IFTTT triggers, I've been looking for a way to automatically archive tweets containing certain search terms of interest to me. Twitter's buil...

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Japan – JGB Yields–More Lattice Charts

May 15, 2013
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Japan – JGB Yields–More Lattice Charts

This blog is littered with posts about Japan. In one sentence, I think Japan presents opportunity and is a very interesting real-time test of much of my macro thinking. Proper visualization is absolutely essential for me to understand all of the dynami...

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Big News! “Practical Data Science with R” MEAP launched!

May 15, 2013
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Big News! “Practical Data Science with R” MEAP launched!

Nina Zumel and I ( John Mount ) have been working very hard on producing an exciting new book called “Practical Data Science with R.” The book has now entered Manning Early Access Program (MEAP) which allows you to subscribe to chapters as they become available and give us feedback before the book goes into Related posts:

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Variance matrix differences

May 15, 2013
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Variance matrix differences

Torturing portfolios to give different volatilities between a factor model and Ledoit-Wolf shrinkage. Previously There have been posts on: “What the hell is a variance matrix?” factor models Ledoit-Wolf shrinkage Question Two of the several ways to produce an estimate of the variance matrix of asset returns is a statistical factor model and Ledoit-Wolf shrinkage.  … Continue reading...

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Forecasting annual totals from monthly data

May 15, 2013
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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...

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Easier confidence interval estimation with matrices and similar arrays in R

May 15, 2013
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When dealing with survey data in particular, social scientists are often wanting to produce proportions from the data, and associated confidence intervals. The prop.test command in R can be used to generate the desired results. When dealing with small ...

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From a random generator to a sample function

May 14, 2013
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From a random generator to a sample function

This week-end, I wrote a post since I had some trouble to generate a sample random sample with R, to reproduce one obtained by a co-author, with SAS (generated using Fishman and Moore (1982) used in function RANUNI). I was lucky since another contributor for that book, Christrophe Dutang, got the anwer to the last question I asked: is it...

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Top 3 R resources for beginners

May 14, 2013
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The community team at Revolution Analytics has just updated this list of resources to learn about R on the Web. Included is this list of the top 3 resources for absolute beginners getting started with R: An Introduction to R – The free, “official” CRAN R Manual Try R – a short course that lets you jump right in...

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Le Monde puzzle [#820]

May 14, 2013
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Le Monde puzzle [#820]

The current puzzle is… puzzling: Given the set {1,…,N} with N<61, one iterates the following procedure: take (x,y) within the set and replace the pair with the smallest divider of x+y (bar 1). What are the values of N such that the final value in the set is 61? I find it puzzling because the

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1.5 percent of doctors, a quarter of malpratice reports

May 14, 2013
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1.5 percent of doctors, a quarter of malpratice reports

Some doctors receive more malpractice reports than others. Just how unequal is the distribution of malpractice reports? The post 1.5 percent of doctors, a quarter of malpratice reports appeared first on Decision Science News.

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SIR Model – The Flue Season – Dynamic Programming

May 14, 2013
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SIR Model – The Flue Season – Dynamic Programming

# The SIR Model (susceptible, infected, and recovered) model is a common and useful tool in epidemiological modelling.# In this post and in future posts I hope to explore how this basic model can be enriched by including different population group...

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Much more efficient bubble sort in R using the Rcpp and inline packages

May 14, 2013
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Recently I wrote a blogpost showing the implementation of a simple bubble sort algorithm in pure R code. The downside of that implementation was that is was awfully slow. And by slow, I mean really slow, as in “a 100… See more ›

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