Students in predominantly ethnic minority classes want segregated education very much. The others don’t.

October 7, 2010
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Students in predominantly ethnic minority classes want segregated education very much. The others don’t.

I just did this for what will hopefully be a book chapter on our Divided Education - Divided Citizens research project with NEPC. Explanation further below for anyone more interested in the actual topic ;-) About the graphic: I like raw-...

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Studying joint effects in a regression

October 7, 2010
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Studying joint effects in a regression

We've seen in the previous post (here)  how important the *-cartesian product to model joint effected in the regression. Consider the case of two explanatory variates, one continuous (, the age of the driver) and one qualitative (, gasoline ve...

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Build a Recommendation System for R Packages

October 7, 2010
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On Dataists, a new collaborative blog for data hackers that I’m contributing to, we’ve just announced a data contest that’s custom made for R users. To win the contest, you need to build a recommendation system for R packages. To find out more, check out the official announcement on Dataists. Then go to GitHub to

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Using Data Tools to Find Data Tools, the Yo Dawg of Data Hacking

October 7, 2010
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by John Myles White and Drew Conway Editors’ Note: One theme likely to recur on dataists.com is that data hackers love using their tools to analyze, visualize, and predict everything. Data hackers also love discovering and learning about new tools. So it should come as no surprise that Dataist contributors John Myles White and Drew

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R is Hot: Part 1

October 7, 2010
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This is Part 1 of a five-part article series, with new parts published each Thursday. You can download the complete article from the Revolution Analytics website. How Did a Statistical Programming Language Invented in New Zealand Become a Global Sensation? Much in the same way that social networking, reality TV and craft beer were considered marginal fads before gaining...

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LondonR Rcpp slides

October 7, 2010
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I'm just back to london where I presented about Rcpp at mango's LondonR event.This was the third time (after rmetrics and useR!) I presented these slides, so I allowed myself some new metaphores about my long term relationship with R and my ind...

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Science is vital – what we don’t know yet

October 6, 2010
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Science is vital – what we don’t know yet

This post is not about R (for a change). For working UK scientists, science is vital – sign the on-line petition to preserve science funding. For my contribution of what we don’t know yet - We don’t know whether we can use biomarkers of kidney injury to personalise the doses of medications to maximise the

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Creating GUIs in R with gWidgets

October 6, 2010
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Creating GUIs in R with gWidgets

The gWidgets framework is a way of creating graphical user interfaces in a toolkit independent way. That means that you can choose between tcl/tk, Gtk, Java or Qt underneath the bonnet. There's also a web-version based upon RApache and ExtJS. Since the code is the same in each case, you can change your mind and swap toolkits...

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R is Hot

October 6, 2010
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Our mission at Revolution Analytics is to make R the statistical analysis tool of choice in the workplace. But even though R is pervasive in academia and rising in popularity generally, we still sometimes get blank faces when we demonstrate R to potential new clients. Sure, most people have heard of R -- it's been hard to miss in...

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Belgian Astronomers and Exercise Machines

October 6, 2010
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Belgian Astronomers and Exercise Machines

In the twisting paths of human discovery, you never quite know what intellectual enterprise is going to result in a world changing discovery.  For instance, the mathematical notion of expected value did not grow up in a sterile, academic environment.   In 1654 Blaise Pascal was approached by Chevalier de Méré who was interested...

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Belgian Astronomers and Exercise Machines

October 6, 2010
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Belgian Astronomers and Exercise Machines

In the twisting paths of human discovery, you never quite know what intellectual enterprise is going to result in a world changing discovery.  For instance, the mathematical notion of expected value did not grow up in a sterile, academic environment.   In 1654 Blaise Pascal was approached by Chevalier de Méré who was interested...

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Convert decimal to IEEE-754 in R

October 6, 2010
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For some theory on the standard IEEE-754, you can read the Wikipedia page. Here I will post only the code of the function to make the conversion in R.First we write some functions to convert decimal numbers to binary numbers:decInt_to_8bit q r xx for(i in 1:precs){xx q r xx }rr return(rr)}devDec_to_8bit nas nbs xxs for(i in 1:precs){xxs...

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Convert decimal to IEEE-754 in R

October 6, 2010
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For some theory on the standard IEEE-754, you can read the Wikipedia page. Here I will post only the code of the function to make the conversion in R.First we write some functions to convert decimal numbers to binary numbers:decInt_to_8bit q r xx for(i in 1:precs){xx q r xx }rr return(rr)}devDec_to_8bit nas nbs xxs for(i in 1:precs){xxs...

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How fast is JAGS?

October 6, 2010
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How fast is JAGS?

From Martyn Plummer, on the JAGS news blog. Key graph below, showing a few outlying cases in which JAGS is substantially slower than OpenBUGS, but generally, JAGS performs quite favorably. Key point from Martyn: Incidentally, these figures are for JAGS with the glm module loaded. The glm module is not loaded by default. If you

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Typos…

October 5, 2010
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Typos…

Edward Kao just sent another typo found both in  Monte Carlo Statistical Methods (Problem 3.21) and in Introducing Monte Carlo Methods with R (Exercise 3.17), namely that should be I also got another email from Jerry Sin mentioning that matrix summation in the matrix commands of Figure 1.2 of Introducing Monte Carlo Methods with R

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The Data Science Venn Diagram

October 5, 2010
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The Data Science Venn Diagram

Whenever I'm asked, "Who uses R?", I usually rattle off a long list of job titles: statistician, analyst, quant, researcher ... and that's before all the domain-specific titles. It would be nice if there were a simple, succinct phrase to describe the process of working with, analyzing, and communicating with real data. At the new blog, "dataists", the inaugural...

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Arctic Sea Ice Extent Trends: 1979-2010; Update 1

October 5, 2010
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Arctic Sea Ice Extent Trends: 1979-2010; Update 1

Now that the 2010 Arctic sea ice melt season is over, we can see how 2010 fits into the long-term trends Arctic  Sea Ice Extent. This post shows an R Climate chart that I have made to look at the … Continue reading →

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Example 8.8: more Hosmer and Lemeshow

October 5, 2010
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Example 8.8: more Hosmer and Lemeshow

This is a special R-only entry.In Example 8.7, we showed the Hosmer and Lemeshow goodness-of-fit test. Today we demonstrate more advanced computational approaches for the test.If you write a function for your own use, it hardly matters what it looks l...

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India Australia test cricket matches over the years

October 5, 2010
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India Australia test cricket matches over the years

If you're like me - chewing your nails, sitting in the same position for the last 2 hours to watch India battle Australia in the Mohali test match and enjoying the fascinating duel, watch how closely these two teams have fought in the past. This plot s...

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India Australia test cricket matches over the years

October 5, 2010
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India Australia test cricket matches over the years

If you're like me - chewing your nails, sitting in the same position for the last 2 hours to watch India battle Australia in the Mohali test match and enjoying the fascinating duel, watch how closely these two teams have fought in the past. This plot s...

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Why R is better than Excel for teaching statistics

October 4, 2010
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Why R is better than Excel for teaching statistics

This was the topic of a recent conversation on the Australian and New Zealand R mailing list. Here is an edited list of some of the comments made. R is free. R is well-documented. R runs (really well) on *nix as well as Windows and Mac OS. R is open-source. Trust in the R software

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S4 classes in R: printing function definition and getting help

October 4, 2010
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I’m not very familiar with S4 classes and methods, but I assume it’s the recommended way to write new packages since it is newer than S3; this of course is open to debate. I’ll outline my experience of programming with S4 classes and methods in a later post, but in the mean time, I want... Read more »

Use R to Analyze Players for your Fantasy Hockey League

October 4, 2010
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Use R to Analyze Players for your Fantasy Hockey League

I am in a fantasy hockey league for the first time this seasons and I wanted to use R to analyze players.  Since I am relatively new to R, I am quite certain this code could be improved.  The code below is functional, however, and while this isn’t my complete analysis, I think it outlines

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Max Heart Rate Calculations Compared

October 4, 2010
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Max Heart Rate Calculations Compared

Physical fitness has become increasingly technical and data driven.  I started running a bit in the last few months and have been delving into the prevailing wisdom related to assessing ones health as a baseline for pursuing various fitness goals....

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Max Heart Rate Calculations Compared

October 4, 2010
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Max Heart Rate Calculations Compared

Physical fitness has become increasingly technical and data driven.  I started running a bit in the last few months and have been delving into the prevailing wisdom related to assessing ones health as a baseline for pursuing various fitness goals....

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Means By

October 4, 2010
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The other day I was asked by a coworker hos to do a SAS Means By statement in R. I embarrassingly did not know how to so I wrote something up, and this is what I came up with, it takes a data.frame and an indexing variable and computes the means for each group defined

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Code Snippets in Revolution R

October 4, 2010
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Ajay Ohri has been trying out the Code Snippets feature in Revolution R (available free to academics), and has found it handy for writing code for statistical analysis: Now even if you are averse to using a GUI /or GUI creators don’t have your particular analysis you can basically type in code at an extremely fast pace. It is...

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The ARIMAX model muddle

October 4, 2010
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The ARIMAX model muddle

There is often confusion about how to include covariates in ARIMA models, and the presentation of the subject in various textbooks and in R help files has not helped the confusion. So I thought I’d give my take on the issue. To keep it simple, I will only describe non-seasonal ARIMA models although the ideas

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A tale of two returns

October 4, 2010
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A tale of two returns

It was the best of times, it was the worst of times. As you may have guessed, this is a mashup of a novel by Charles Dickens and an explanation of financial returns. The key plot element of A Tale of Two Cities is that there are two men, Charles Darnay and Sydney Carton, who … Continue reading...

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