Data Analysis in Excel

November 26, 2013
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Using a spreadsheet for doing data analysis can be very efficient but also due to the very flexible nature of a spreadsheet a little thought is required before filling cells with data. Typically when using a statistical software package data is loaded ...

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Not only verbs but also believes can be conjugated

November 26, 2013
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Not only verbs but also believes can be conjugated

Following on from last week, where I presented a simple example of a Bayesian network with discrete probabilities to predict the number of claims for a motor insurance customer, I will look at continuos probability distributions today. Here I follow ex...

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getSymbols Extra

November 26, 2013
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getSymbols Extra

The getSymbols function from the quantmod package is an easy and convenient way to bring historical stock prices into your R environment. You need to specify the list of tickers, the source of historical prices and dates. For example following commands will download historical stock prices from yahoo finance for ‘RWX’, ‘VNQ’, ‘VGSIX’ symbols: Now, […]

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Book review: Practical Data Analysis

November 25, 2013
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Book review: Practical Data Analysis

Many people have drawn Venn diagrams to locate machine learning and related ideas in the intellectual landscape. Drew Conway’s diagram may have been the first. It has at least been frequently referenced. By this classification, Hector Cuesta’s new book Practical Data Anaysis is located toward the “hacking skills” corner of the diagram. No single book […]

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Getting Started with Mixed Effect Models in R

November 25, 2013
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Getting Started with Multilevel Modeling in R Getting Started with Multilevel Modeling in R Jared E. Knowles Introduction Analysts dealing with grouped data and complex hierarchical structures in their data ranging from measu...

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Six Ways Coding Teaches Math

November 25, 2013
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Six Ways Coding Teaches Math

Last week I attended the Computer-Based Mathematics Education Summit in New York City, run by Wolfram Research and hosted at UNICEF headquarters.The motivation behind the summit is explained by Conrad Wolfram in this TED talk.  His idea is that ma...

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Where Students Study Abroad via the European Erasmus Network

November 25, 2013
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Where Students Study Abroad via the European Erasmus Network

Erasmus is an European Union student exchange program that allows more than 75.000 European students to travel abroad and study in a country different from their home. The network consists of over 2.900 universities, which are interconnected by over 9...

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An interesting but flawed attempt to apply general forecasting principles to contextualize attitudes toward risks of global warming

November 25, 2013
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An interesting but flawed attempt to apply general forecasting principles to contextualize attitudes toward risks of global warming

I came across a document [updated link here], “Applying structured analogies to the global warming alarm movement,” by Kesten Green and Scott Armstrong. The general approach is appealing to me, but the execution seemed disturbingly flawed. Here’s how they introduce the project: The structured analogies procedure we [Green and Armstrong] used for this study was […]The post An interesting but flawed attempt to apply general forecasting principles to contextualize attitudes…

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TSA gets into the randomization game

November 25, 2013
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Surprise surprise. On my way to and from Raleigh last week, I became part of a randomized experiment! At the entrance to the security check, there was a tablet (iPad?) perched on a stand that randomized passengers into the left line or the right line. I encountered the same setup on the return leg. On the outbound leg, I was assigned to the control group while on the trip back,…

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Involuntary head tilt

November 25, 2013
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Involuntary head tilt

A data graphic's first mission is communications. Looking cute should not come before. This one is a big fail by MIT Technology Review (link). What makes the designer want to tilt the reader's head? This chart is unreadable. It also...

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Collaboration Distance and the Math Genealogy Project

November 25, 2013
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The American Mathematical Society has a fun site on "collaboration distance" between various mathematicians. The idea is simple: If, for example, I wrote with X, and X wrote with Z, then my collaboration distance to Z is two. There's a good d...

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Twelve advantages to calling R from the SAS/IML language

November 25, 2013
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Twelve advantages to calling R from the SAS/IML language

For several years, there has been interest in calling R from SAS software, primarily because of the large number of special-purpose R packages. The ability to call R from SAS has been available in SAS/IML since 2009. Previous blog posts about R include a video on how to call R [...]

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Postdoc position on psychometrics and network modeling

November 25, 2013
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Francis Tuerlinckx announces that he and Denny Borsboom have a joint postdoctoral position. It sounds really cool: The position is in the Research Group of Quantitative Psychology and Individual Differences at the University of Leuven (Belgium) and involves frequent travel to and contact with the Psychological Methods group in Amsterdam. The research of the postdoc […]The post Postdoc position on psychometrics and network modeling appeared first on Statistical Modeling, Causal…

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Hidden dangers of a sloppy understanding of probabilities

November 25, 2013
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Andrew Gelman’s new favorite example of the hidden dangers of noninformative priors is the following. If we observe data y ~ N(theta,1) and get y=1, then this is consistent with being pure noise, but the posterior probability for theta>0 is .84. ...

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How to get your paper rejected quickly

November 25, 2013
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How to get your paper rejected quickly

I sent this rejection letter this morning about a paper submitted to the International Journal of Forecasting. Dear XXXXX. I am writing to you regarding manuscript ????? entitled “xxxxxxxxxxxx” which you submitted to the International Journal of Forecasting. It so happens that I am aware that this paper was previously reviewed for the YYYYYYY journal. It seems that you have not bothered to make any of the changes recommended by…

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Buffon needled R exams

November 24, 2013
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Buffon needled R exams

Here are two exercises I wrote for my R mid-term exam in Paris-Dauphine around Buffon’s needle problem. In the end, the problems sounded too long and too hard for my 3rd year students so I opted for softer questions. So recycle those if you wish (but do not ask for solutions!) Filed under: Books, Kids, […]

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Dutch Rainwater Composition 1992-2011

November 24, 2013
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Dutch Rainwater Composition 1992-2011

Last week I examined rainwater composition 1992 to 2005. There is additional data, but National Institute for Public Health has changed equipment in 2005. This week I will add those data.DataData is in a number of spreadsheets. The scrip...

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R: Mapping Super Typhoon Yolanda (Haiyan) Track

November 24, 2013
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R: Mapping Super Typhoon Yolanda (Haiyan) Track

After reading Enrico Tonini post, I decided to map the super typhoon Haiyan track using OpenStreetMap, maptools, and ggplot2. If mapping with googleVis was possible with 13 lines only, that can also be achieved with the packages I used; but because I p...

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Simulation speed: GNU R vs Julia

November 23, 2013
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Simulation speed: GNU R vs Julia

Recently there is a lot of noise about Julia. I have decided to test its speed in simulation tasks on my toy Cont model. I thought I had vectorized my GNU R code pretty well, but Julia is much faster.The model was described in my earlier posts so let u...

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Simudidactic

November 23, 2013
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Simudidactic

auto·di·dact n. A self-taught person. From Greek autodidaktos, self-taught : auto-, auto- + didaktos, taught; + sim·u·late v. To create a representation or model of (a physical system or particular situation, for example). From Latin simulre, simult-, from similis, like; = (If you can get past the mixing of Latin and Greek roots) sim·u·di·dactic adj. To learn by creating a representation or model of a physical system or […]

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Tables > figures yet again

November 23, 2013
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I received the following email from someone who would like to remain anonymous: A journal editor made me change all my figures into tables. I complied, but I sent along one of your papers on the topic of figures versus tables. I got the following email in response which I thought you’d find funny: Yes, […]The post Tables > figures yet again appeared first on Statistical Modeling, Causal Inference, and…

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Le Monde puzzle [#840]

November 22, 2013
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Le Monde puzzle [#840]

Another number theory Le Monde mathematical puzzles: Find 2≤n≤50 such that the sequence {1,…,n} can be permuted into a sequence such that the sum of two consecutive terms is a prime number.  Now this is a problem with an R code solution: which returns the solution as and so it seems there is no solution beyond N=12… […]

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Compiling R from source and why you shouldn’t do it

November 22, 2013
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Compiling R from source and why you shouldn’t do it

I’ve always thought that it’s silly, in most cases, source compiling software that’s already available in binary form. To the end of making more binary packages available to Mac users, I just started contributing to a project that is creating a repository of 64 bit builds of pkgsrc’s (NetBSD's portable package manager) over 12,000 packages. »more

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