JHU Data Science: More is More

May 5, 2014
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Today Jeff Leek, Brian Caffo, and I are launching 3 new courses on Coursera as part of the Johns Hopkins Data Science Specialization. These courses are Exploratory Data Analysis Reproducible Research Statistical Inference I'm particularly excited about Reproducible Research, not … Continue reading →

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7 R Quirks That Will Drive You Nutty

May 5, 2014
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7 R Quirks That Will Drive You Nutty

7 R Quirks That Will Drive You Nutty StumpedEvery language has its idiosyncrasies. Some “designer”“ type languages have less due to extreme thoughtfulness of language engineers. I suspect Julia for example has many less quirks. However, despite its quirkiness R has become an amazingly flexible resource for a diverse range of tasks with thousands of packages and over 100,000 available commands (Rdocumentation.org) in subject matter as diverse as Pharmacokinetics, to…

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On deck this month

May 5, 2014
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Can we make better graphs of global temperature history? Priors I don’t believe Cause he thinks he’s so-phisticated Discussion with Steven Pinker on research that is attached to data that are so noisy as to be essentially uninformative Combining forecasts: Evidence on the relative accuracy of the simple average and Bayesian model averaging for predicting […] The post On deck this month appeared first on Statistical Modeling, Causal Inference, and…

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Going overboard with simplicity

May 5, 2014
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Going overboard with simplicity

Today I look at an unlikely oversight by the New York Times: I think they tried to simplify the scale but ended up making a mess. Tufte preaches getting rid of all unnecessary ink but sometimes, you go overboard. ***...

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Blanks and lengths: Understanding SAS/IML character vectors

May 5, 2014
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Blanks and lengths: Understanding SAS/IML character vectors

SAS programmers are probably familiar with how SAS stores a character variable in a data set, but how is a character vector stored in the SAS/IML language? Recall that a character variable is stored by using a fixed-width storage structure. In the SAS DATA step, the maximum number of characters […]

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Stan (& JAGS) Tutorial on Linear Mixed Models

May 4, 2014
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Shravan Vasishth sent me an earlier draft of this tutorial he co-authored with Tanner Sorensen. I liked it, asked if I could blog about it, and in response, they’ve put together a convenient web page with links to the tutorial PDF, JAGS and Stan programs, and data: Fitting linear mixed models using JAGS and Stan: […] The post Stan (& JAGS) Tutorial on Linear Mixed Models appeared first on Statistical…

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Honored oldsters write about statistics

May 4, 2014
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The new book titled: Past, Present, and Future of Statistical Science is now available for download. The official description makes the book sound pretty stuffy: Past, Present, and Future of Statistical Science, commissioned by the Committee of Presidents of Statistical Societies (COPSS) to celebrate its 50th anniversary and the International Year of Statistics, will be […] The post Honored oldsters write about statistics appeared first on Statistical Modeling, Causal Inference,…

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New jobs in business analytics at Monash

May 4, 2014
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New jobs in business analytics at Monash

We have an exciting new initiative at Monash University with some new positions in business analytics. This is part of a plan to strengthen our research and teaching in the data science/computational statistics area. We are hoping to make multiple appointments, at junior and senior levels. These are five-year appointments, but we hope that the positions will continue after that if we can secure suitable funding. What is business analytics?…

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Choropleths and Bar charts of State Wise Potentially Preventable Deaths using googleVis and shiny

May 4, 2014
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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/1mcofpp. PLEASE UPDATE ANY BOOKMARKS YOU MAY HAVE.

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European MEP Data

May 4, 2014
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European MEP Data

Pretty soon we will be having European Elections. I cannot tell when exactly, that depends on country. Over here the elections get a some attention, which is how I ran into data from votewatch.eu on voting of MEPs. That was just too interesting, so I m...

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GrubHub’s Phasmid Websites

May 4, 2014
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GrubHub’s Phasmid Websites

The rationale behind mining business data directly from the business's own website is that the business has a clear economic motivation to ensure that the data is up to date. If you own a restaurant that changes location, and your...

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Jeffreys’ Substitution Posterior for the Median: A Nice Trick to Non-parametrically Estimate the Median

May 4, 2014
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Jeffreys’ Substitution Posterior for the Median: A Nice Trick to Non-parametrically Estimate the Median

While reading up on quantile regression I found a really nice hack described in Bayesian Quantile Regression Methods (Lancaster & Jae Jun, 2010). It is called Jeffreys’ substitution posterior for the median, first described by Harold Jeffreys i...

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You can only become coherent by ‘converting’ non-Bayesianly

May 4, 2014
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You can only become coherent by ‘converting’ non-Bayesianly

“What ever happened to Bayesian foundations?” was one of the final topics of our seminar (Mayo/SpanosPhil6334). In the past 15 years or so, not only have (some? most?) Bayesians come to accept violations of the Likelihood Principle, they have also tended to disown Dutch Book arguments, and the very idea of inductive inference as updating beliefs by […]

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A clear picture of power and significance in A/B tests

May 3, 2014
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A clear picture of power and significance in A/B tests

A/B tests are one of the simplest reliable experimental designs. Controlled experiments embody the best scientific design for establishing a causal relationship between changes and their influence on user-observable behavior. “Practical guide to controlled experiments on the web: listen to your customers not to the HIPPO” Ron Kohavi, Randal M Henne, and Dan Sommerfield, Proceedings […] Related posts: Bandit Formulations for A/B Tests: Some Intuition Sample size and power for…

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“The graph clearly shows that mammography adds virtually nothing to survival and if anything, decreases survival (and increases cost and provides unnecessary treatment)”

May 3, 2014
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“The graph clearly shows that mammography adds virtually nothing to survival and if anything, decreases survival (and increases cost and provides unnecessary treatment)”

Paul Alper writes: You recently posted on graphs and how to convey information.  I don’t believe you have ever posted anything on this dynamite randomized clinical trial of 90,000 (!!) 40-59 year-old women over a 25-year period (also !!). The graphs below are figures 2, 3 and 4 respectively, of http://www.bmj.com/content/348/bmj.g366 The control was physical […] The post “The graph clearly shows that mammography adds virtually nothing to survival and…

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How to do a chi-square test in 7 steps

May 3, 2014
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How to do a chi-square test in 7 steps

What is a chi-square test: A chi square tests the relationship between two attributes. Suppose we suspect that rural Americans tended to vote Romney, and urban Americans tended to vote Obama. In this case, we suspect a relationship between where you live and who you vote for. The full name for this test is Pearson’s […]

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Calendar Strategy: Option Expiry

May 3, 2014
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Calendar Strategy: Option Expiry

Today, I want to follow up with the Calendar Strategy: Month End post. Let’s examine the perfromance Option Expiry days as presented in the The Mooost Wonderful Tiiiiiiime of the Yearrrrrrrrr! post. First, I created two convenience functions for creating a calendar signal and back-testing calendar strategy: calendar.signal and calendar.strategy functions are in the strategy.r […]

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The May Reading List

May 2, 2014
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The May Reading List

Bjerkholt, O., 2013. Promoting econometrics through Econometrica 1933-39. Memorandum 28/2013, Department of Economics, University of Oslo.Gulesserian, S. G. and M. Kejriwal, 2014. On the power of bootstrap tests for stationarity: A Monte Carlo comparis...

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Discovering general multidimensional associations

May 2, 2014
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Continuing our discussion of general measures of correlations, Ben Murrell sends along this paper (with corresponding R package), which begins: When two variables are related by a known function, the coefficient of determination (denoted R-squared) measures the proportion of the total variance in the observations that is explained by that function. This quantifies the strength […] The post Discovering general multidimensional associations appeared first on Statistical Modeling, Causal Inference, and…

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In the media

May 2, 2014
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In the media

Yesterday, UCL News Office issued this press release which mentions our (that's Marta and me) paper on the Eurovision contest, which has just been published in the Journal of Applied Statistics.The idea of the paper was to try and quantify the presence...

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Multidimensional Scaling (MDS) with R

May 2, 2014
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Multidimensional Scaling (MDS) with R

This page shows Multidimensional Scaling (MDS) with R. It demonstrates with an example of automatic layout of Australian cities based on distances between them. The layout obtained with MDS is very close to their locations on a map. At first, … Continue reading →

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On demand (but on a very serious topic)

May 2, 2014
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My friend Virgilio has posted this on his Facebook page and invited me to comment. It is an article by a Spanish cardiologist that tells the story of a patient who has suffered a second stroke in a short amount of time $-$ as it turns out, th...

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Why Blog?

May 2, 2014
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Why Blog?

The Blog Review ProcessA series of events in my life have lead me to reconsider the value of blogging.The Back StoryShort story: I got fired.Long story: Recently I was hired to write occasional blog posts for Quandl. They probably figured that due to m...

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