“Heterogeneity of variance in experimental studies: A challenge to conventional interpretations”

June 9, 2013
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Avi sent along this old paper from Bryk and Raudenbush, who write: The presence of heterogeneity of variance across groups indicates that the standard statistical model for treatment effects no longer applies. Specifically, the assumption that treatments add a constant to each subject’s development fails. An alternative model is required to represent how treatment effects [...]The post “Heterogeneity of variance in experimental studies: A challenge to conventional interpretations” appeared first…

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R: Quartiles, Deciles, and Percentiles

June 9, 2013
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The measures of position such as quartiles, deciles, and percentiles are available in quantile function. This function has a usage,where:x - the data pointsprob - the location to measurena.rm - if FALSE, NA (Not Available) data points are not ignoredna...

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Quick and Simple D3 Network Graphs from R

June 9, 2013
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Quick and Simple D3 Network Graphs from R

Sometimes I just want to quickly make a simple D3 JavaScript directed network graph with data in R. Because D3 network graphs can be manipulated in the browser–i.e. nodes can be moved around and highlighted–they're really nice for data...

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R: Mean and Median

June 9, 2013
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Mean in R is computed using the function mean. Consider the scores of 20 MSU-IIT students in Stat 101 exam with a hundred items: 70, 78, 66, 65, 50, 53, 48, 88, 95, 80, 85, 84, 81, 63, 68, 73, 75, 84, 49, and 77. Compute and interpret the mean and medi...

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New Judea Pearl journal of causal inference

June 8, 2013
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Pearl reports that his Journal of Causal Inference has just posted its first issue, which contains a mix of theoretical and applied papers. Pearl writes that they welcome submissions on all aspects of causal inference. The post New Judea Pearl journa...

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Richard Gill: “Integrity or fraud… or just quesionable research practices?”

June 8, 2013
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Richard Gill: “Integrity or fraud… or just quesionable research practices?”

Professor Richard Gill Statistics Group Mathematical Institute Leiden University http://www.math.leidenuniv.nl/~gill/ I am very grateful to Richard Gill for permission to post an e-mail from him (after my “dirty laundry” post) along with slides from his talk, “Integrity or fraud… or just questionable research practices?” and associated papers. I record my own reflections on the pseudoscientific […]

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Using trends in R-squared to measure progress in criminology??

June 8, 2013
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Torbjørn Skardhamar writes: I am a sociologist/criminologist working at Statistics Norway. As I am not a trained statistician, I find myself sometimes in need to check basic statistical concepts. Recently, I came across an article which I found a bit strange, but I needed to check up on my statistical understanding of a very basic [...]The post Using trends in R-squared to measure progress in criminology?? appeared first on Statistical…

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R: Matrix Operations

June 8, 2013
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Matrix manipulation in R are very useful in Linear Algebra. Below are lists of common yet important functions in dealing operations with matrices:Transpose - tMultiplication - %*%Determinant - detInverse - solve, or ginv of MASS libraryEigenvalues and ...

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Hey, I Just Did a Significance Test!

June 8, 2013
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Hey, I Just Did a Significance Test!

I’ve seen it happens quite often. The sig test. Somebody simply needs to know the p-value and that one number will provide all of the information about the study that they need to know. The dataset is presented and the client/boss/colleague/etc invariably asks the question “is it significant?” and “what’s the correlation?”. To quote R.A. […]

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Robust logistic regression

June 7, 2013
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Corey Yanofsky writes: In your work, you’ve robustificated logistic regression by having the logit function saturate at, e.g., 0.01 and 0.99, instead of 0 and 1. Do you have any thoughts on a sensible setting for the saturation values? My intuition suggests that it has something to do with proportion of outliers expected in the [...]The post Robust logistic regression appeared first on Statistical Modeling, Causal Inference, and Social Science.

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ENCODE ChIP-Seq Significance Tool: Which TFs Regulate my Genes?

June 7, 2013
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ENCODE ChIP-Seq Significance Tool: Which TFs Regulate my Genes?

I collaborate with several investigators on gene expression projects using both microarray and RNA-seq. After I show a collaborator which genes are dysregulated in a particular condition or tissue, the most common question I get is "what are the transc...

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Points: Smart Robotic Street Sign Rotates towards Direction of Content

June 7, 2013
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Points: Smart Robotic Street Sign Rotates towards Direction of Content

Points [breakfastny.com] by futuristic product development studio Breakfast is a new kind of street sign that dynamically rotates towards the direction of the real-time content it is showing. The directional street sign consists of 3 separate arms po...

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Bayes, credit scoring and terrorism

June 7, 2013
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Bayes, credit scoring and terrorism

Once again, my neighbor Corey did publish a very interesting post on his blog http://bayesianbiologist.com/… on how likely the NSA program will catch a terrorist (a real one). I was working on something similar last weeks, with Stéphane Tufféry, for our chapter, entitled Statistical Learning in Actuarial Science. The idea was to show credit scoring techniques, from logistic regression, classification trees, random forests, etc. Of course, it is more boring, since…

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“Happy Money: The Science of Smarter Spending”

June 7, 2013
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“Happy Money:  The Science of Smarter Spending”

Sometimes I get books in the mail with titles like, Statistics for Everyone, or Whassup with American Politics?, and I don’t know what to say about them because I’m clearly not their target audience: from my work, I already pretty much know everything that’s going to be in those books. Yesterday, though, what came in [...]The post “Happy Money: The Science of Smarter Spending” appeared first on Statistical Modeling, Causal…

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R: Data Class Conversion

June 7, 2013
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Data in R can be converted from one class to the other. The function is prefixed with as. then followed by the name of the data class that we wish to convert to. Data class in R are the following:numeric - as.numericvector - as.vectorcharacter - as.cha...

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Anything Tests Can do, CIs do Better; CIs Do Anything Better than Tests?* (reforming the reformers cont.)

June 7, 2013
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Anything Tests Can do, CIs do Better; CIs Do Anything Better than Tests?* (reforming the reformers cont.)

Having reblogged the 5/17/12 post on “reforming the reformers” yesterday, I thought I should reblog its follow-up: 6/2/12. Consider again our one-sided Normal test T+, with null H0: μ < μ0 vs μ >μ0  and  μ0 = 0,  α=.025, and σ = 1, but let n = 25. So M is statistically significant only if it exceeds .392. Suppose M (the […]

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How likely is the NSA PRISM program to catch a terrorist?

June 7, 2013
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How likely is the NSA PRISM program to catch a terrorist?

Recent revelations about PRISM, the NSA’s massive program of surveillance of civilian communications have caused quite a stir. And rightfully so, as it appears that the agency has been granted warrantless direct access to just about any form of digital communication engaged in by American citizens, and that their access to such data has been […]

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Leahy Versus Albedoman and the Moneygoround, Part One

June 6, 2013
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Leahy Versus Albedoman and the Moneygoround, Part One

Edward Wyatt reports: Now the Obama administration is cracking down on what many call patent trolls, shell companies that exist merely for the purpose of asserting that they should be paid . . . “The United States patent system is vital for our economic growth, job creation, and technological advance,” [Senator] Leahy said in a [...]The post Leahy Versus Albedoman and the Moneygoround, Part One appeared first on Statistical Modeling,…

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R: Inputting Data in Matrix Format

June 6, 2013
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Matrix in R is formed using matrix, rbind, or cbind function. These functions have the following descriptions:matrix - used to transform a concatenated data into matrix form of compatible dimensions. rbind - short for row bind, that binds a conca...

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Dampened by Google

June 6, 2013
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Dampened by Google

Robert Kosara has a great summary of the "banking to 45 degrees" practice first proposed by Bill Cleveland (link). Roughly speaking, the idea is that the slope of a line chart should be close to 45 degrees for the best...

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VIS Tutorials and the Industry and Government Experiences Track

June 6, 2013
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The deadline for tutorial proposals for VIS 2013 is coming up. There are a few changes from last year. Also, there is a new Industry and Government Experiences Track at the conference this year. Tutorials There are two main changes to tutorials: first, we no longer accept full-day tutorials, only half-day. The goal is to bring in more variety and to focus the tutorials more on specific things rather than being…

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NeuroKnitting: Knitting a Personalized Scarf from Brainwave Activity

June 5, 2013
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NeuroKnitting: Knitting a Personalized Scarf from Brainwave Activity

NeuroKnitting [knitic.com] by Varvara Guljajeva, Mar Canet, and Sebastian Mealla consists of a collection of knitted garments that represent the wearer's affective and cognitive states while listening to Bach's Goldberg Variations' aria and its first ...

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Eurovision Tracker: the Twitter Buzz and Conversations per Country

June 5, 2013
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Eurovision Tracker: the Twitter Buzz and Conversations per Country

Eurovision Tracker [brandwatch.com] by social analytics company Brandwatch provides a visual overview of the Twitter buzz during the live Eurovision final that took place on 18th May. In this streamgraph visualization, each colored stream represent...

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