Multicollinearity tutoral

November 11, 2013
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Multicollinearity tutoral

I just posted brief multicollinearity tutorial on my other blog (loosely based on the material from the Serious Stats book). You can read it here.Filed under: serious stats, stats advice Tagged: correlation and covariance, general linear model, messy d...

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A statistical review of ‘Thinking, Fast and Slow’ by Daniel Kahneman

November 11, 2013
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A statistical review of ‘Thinking, Fast and Slow’ by Daniel Kahneman

I failed to find Kahneman’s book in the economics section of the bookshop, so I had to ask where it was.  “Oh, that’s in the psychology section.”  It should have also been in the statistics section. He states that his collaboration with Amos Tversky started with the question: Are humans good intuitive statisticians? The wrong […] The post A statistical review of ‘Thinking, Fast and Slow’ by Daniel Kahneman appeared…

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cMDS: visualising changing distances

November 11, 2013
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cMDS: visualising changing distances

Gina Gruenhage has just arxived a new paper describing an algorithm we call cMDS. Here’s what it’s for: if you do any kind of data analysis you often find yourself comparing datapoints using some kind of distance metric. All’s well if you have a unique reasonable distance metric you can use, but often what you […]

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A Guide to the Quality of Different Visualization Venues

November 11, 2013
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A Guide to the Quality of Different Visualization Venues

I recently got an email from a colleague with the subject, “Academic research, is it all bad?” He had looked at a paper presented at a VIS workshop that people were pointing to on Twitter, and had found it lacking (“it’s just a blog posting”). While there are high-quality venues for visualization research, it’s not easy to be sure which ones are good, and which ones are lower quality.

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Schiminovich is on The Simpsons

November 10, 2013
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Schiminovich is on The Simpsons

OK, fine. Maybe they could work Stan on to the show next? I thought I could retire once I’d successfully inserted the phrase “multilevel regression and poststratification” into the NYT, but now I want more more more. Maybe a cage ...

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The GCD and LCM functions in SAS

November 10, 2013
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The GCD and LCM functions in SAS

My daughter's middle school math class recently reviewed how to compute the greatest common factor (GCF) and the least common multiple (LCM) of a set of integers. (The GCF is sometimes called the greatest common divisor, or GCD.) Both algorithms require factoring integers into a product of primes. While helping [...]

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A small comparison of bio-equivalence calculations.

November 10, 2013
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Last week I looked at two-way cross-over studies and followed the example of Schütz (http://bebac.at/) in the analysis. Since the EU has its on opinions (Questions & Answers: Positions on specific questions addressed to the pharmacokinetics workin...

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Modèle de régression et interaction(s) entre facteurs

November 10, 2013
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Modèle de régression et interaction(s) entre facteurs

Dans un modèle de régression, on veut écrire Quand on se limite à un modèle linéaire, on écrit Mais on de doute que l’on rate quelque chose… en particulier, on va rater toutes les interactions possibles. On peut croiser les variables, et supposer que qui peut s’étendre d’avantage, à l’ordre 3, voire davantage. Supposons que nos variables  soient ici qualitatives, et plus précisément binaires. Prenons un exemple simple, avec des données…

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Beware of questionable front page articles warning you to beware of questionable front page articles (iii)

November 10, 2013
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Beware of questionable front page articles warning you to beware of questionable front page articles (iii)

In this time of government cut-backs and sequester, scientists are under increased pressure to dream up ever new strategies to publish attention-getting articles with eye-catching, but inadequately scrutinized, conjectures. Science writers are under similar pressures, and to this end they have found a way to deliver up at least one fire-breathing, front page article a […]

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Keynote speaker

November 9, 2013
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Keynote speaker

Earlier today, I was trying to finish preparing the poster for the Clinical Trials Methodology Conference $-$ I'll have both the poster presentation (on the Expected Value of Information under mixed strategies) and my talk on the Stepped Wedge des...

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Typo in Ghitza and Gelman MRP paper

November 9, 2013
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Typo in Ghitza and Gelman MRP paper

Devin Caughey points out a typo in the second column of page 765 of our AJPS paper. Here’s what we have: The typo is in the third line of the second paragraph above. Where it says y^*_j = y.bar^*_j n_j, it should be y^*_j = y.bar^*_j n^*_j. One frustrating system of the current system of […]The post Typo in Ghitza and Gelman MRP paper appeared first on Statistical Modeling, Causal…

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Multicollinearity and collinearity (in multiple regression) – a tutorial

November 9, 2013
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Multicollinearity and collinearity (in multiple regression) – a tutorial

This blog post was written for undergraduate research methods teaching. I have therefore tried to keep everything relatively simple and equation-free. The content is based loosely on more detailed material in my book Serious stats. What are collineari...

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Null Effects and Replication

November 9, 2013
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Null Effects and Replication

Filed under: Comedy, Error Statistics, Statistics

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Maximum Likelihood versus Goodness of Fit

November 9, 2013
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Maximum Likelihood versus Goodness of Fit

Thursday, I got an interesting question from a colleague of mine (JP). I mean, the way I understood the question turned out to be a nice puzzle (but I have to confess I might have misunderstood). The question is the following : consider a i.i.d. sample of continuous variables. We would like to choose between two (parametric) families for the distribution,  and . If we use maximum likelihood techniques, we…

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Key Driver vs. Network Analysis in R

November 8, 2013
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Key Driver vs. Network Analysis in R

When marketing researchers speak of driver analysis, they are referring to an input-output model with overall satisfaction as the output and performance ratings of specific product and service components as the inputs. The causal model is straightforwa...

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Generating functions

November 8, 2013
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Generating functions

Today, I wanted to publish a post on generating functions, based on discussions I had with Jean-Francois while having our coffee after lunch a couple of times already. The other reason is that I publish my post while my student just finished their Probability exam (and there were a few questions on generating functions). A short introduction (back on a specific exercise) In the Probability exam, I included an exercise we’ve…

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Translating between R and SQL: the basics

November 8, 2013
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An introductory comparison of using the two languages. Background R was made especially for data analysis and graphics.  SQL was made especially for databases.  They are allies. The data structure in R that most closely matches a SQL table is a data frame.  The terms rows and columns are used in both. A mashup There […] The post Translating between R and SQL: the basics appeared first on Burns Statistics.

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A day with the news!

November 8, 2013
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A day with the news!

One great thing about working in statistics and political science is, between them, these two subjects are connected to just about everything. From the day’s news (sort of): Pat Robertson Thinks Low-Carb Diets Violate God’s Principles: I wonder what Art De Vany will think of this. I had the impression that lo-carb is vaguely connected […]The post A day with the news! appeared first on Statistical Modeling, Causal Inference, and…

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Financial Data Accessible from R – part III

November 8, 2013
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I came across a new source of data which I think is really worth sharing: ThinkNum. It gathers around 2,000 sources of data but more importantly it allows the user to manipulate this data via functions and graphics and there is an R package available on CRAN. Interested readers can find a very good post […]

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Rescue remedy

November 7, 2013
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Rescue remedy

Interesting day, today. I woke up really early (3.45am) to catch my flight to Amsterdam to give my talk at the Chemometrics Workshop. The cab got me to the airport early enough so that I could clear security, have a coffee and slowly make my way to the...

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Replication of few graphs/charts in base R, ggplot2, and rCharts

November 7, 2013
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UPDATE: THE BLOG/SITE HAS MOVED TO GITHUB. THE NEW LINK FOR THE BLOG/SITE IS patilv.github.io and THE LINK TO THIS POST IS: http://bit.ly/1jJ6f7v. PLEASE UPDATE ANY BOOKMARKS YOU MAY HAVE.In this post, I use a simulated dataset (7 variables -3 factor a...

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The e-Writing Jungle Part 1: LaTeX to pdf to the Web

November 7, 2013
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LaTeX and MathML and MathJax and Python and Sphinx and IPython and R and Knitter and Firefox and Chrome and ...My head is spinning with all this stuff. Maybe yours is too.One thing is clear: The traditional academic book publishing paradigm (broadly de...

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I’m negative on the expression “false positives”

November 7, 2013
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After seeing a document sent to me and others regarding the crisis of spurious, statistically-significant research findings in psychology research, I had the following reaction: I am unhappy with the use in the document of the phrase “false positives.” I feel that this expression is unhelpful as it frames science in terms of “true” and […]The post I’m negative on the expression “false positives” appeared first on Statistical Modeling, Causal…

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