Looking for Bayesian expertise in India, for the purpose of analysis of sarcoma trials

April 16, 2014
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Prakash Nayak writes: I work as a musculoskeletal oncologist (surgeon) in Mumbai, India and am keen on sarcoma research. Sarcomas are rare disorders, and conventional frequentist analysis falls short of providing meaningful results for clinical application. I am thus keen on applying Bayesian analysis to a lot of trials performed with small numbers in this […] The post Looking for Bayesian expertise in India, for the purpose of analysis of…

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The reality is most A/B tests fail, and Facebook is here to help

April 16, 2014
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Two years ago, Wired breathlessly extolled the virtues of A/B testing (link). A lot of Web companies are in the forefront of running hundreds or thousands of tests daily. The reality is that most A/B tests fail. A/B tests fail for many reasons. Typically, business leaders consider a test to have failed when the analysis fails to support their hypothesis. "We ran all these tests varying the color of the…

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Errors on percentage errors

April 16, 2014
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Errors on percentage errors

The MAPE (mean absolute percentage error) is a popular measure for forecast accuracy and is defined as     where denotes an observation and denotes its forecast, and the mean is taken over . Armstrong (1985, p.348) was the first (to my knowledge) to point out the asymmetry of the MAPE saying that “it has a bias favoring estimates that are below the actual values”. A few years later, Armstrong…

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The Granville incident

April 16, 2014
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The Granville incident

Earlier this morning, there was some commotion on the allstat mailing list (if you don't know what it is, that's a UK-based discussion list specifically focussed on statistics; it's been active for quite some time and usually you get useful information...

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On the determinant of the Hilbert matrix

April 16, 2014
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On the determinant of the Hilbert matrix

Last week I described the Hilbert matrix of size n, which is a famous square matrix in numerical linear algebra. It is famous partially because its inverse and its determinant have explicit formulas (that is, we know them exactly), but mainly because the matrix is ill-conditioned for moderate values of […]

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A. Spanos: Jerzy Neyman and his Enduring Legacy

April 16, 2014
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A. Spanos: Jerzy Neyman and his Enduring Legacy

A Statistical Model as a Chance Mechanism Aris Spanos  Jerzy Neyman (April 16, 1894 – August 5, 1981), was a Polish/American statistician[i] who spent most of his professional career at the University of California, Berkeley. Neyman is best known in statistics for his pioneering contributions in framing the Neyman-Pearson (N-P) optimal theory of hypothesis testing […]

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Econometric Game, 2014

April 15, 2014
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Econometric Game, 2014

I've blogged about The Econometric Game previously - see here, here,  and here.It's April, so the Game is on again - today and the next two days, to be specific. You can check out he details, as they become available, at this site.Good luck to all...

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Video Tutorial – Rolling 2 Dice: An Intuitive Explanation of The Central Limit Theorem

Video Tutorial – Rolling 2 Dice: An Intuitive Explanation of The Central Limit Theorem

According to the central limit theorem, if random variables, , are independent and identically distributed, is sufficiently large, then the distribution of their sample mean, , is approximately normal, and this approximation is better as increases. One of the most remarkable aspects of the central limit theorem (CLT) is its validity for any parent distribution of […]

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Timid medical research

April 15, 2014
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-+*Cancer research is sometimes criticized for being timid. Drug companies run enormous trials looking for small improvements. Critics say they should run smaller trials and more of them. Which side is correct depends on what’s out there waiting to be discovered, which of course we don’t know. We can only guess. Timid research is rational […]

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Conventions, novelty and the double edge

April 15, 2014
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Conventions, novelty and the double edge

This chart from Reuters is making the rounds on Twitter today. Quickly, tell me whether the Gun Law in Florida did well or poorly. That of course is the entire purpose of the chart. *** If you are like me,...

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When you believe in things that you don’t understand

April 15, 2014
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When you believe in things that you don’t understand

This would make Karl Popper cry. And, at the very end: The present results indicate that under certain, theoretically predictable circumstances, female ovulation—long assumed to be hidden—is in fact associated with a distinct, objectively observable behavioral display. This statement is correct—if you interpret the word “predictable” to mean “predictable after looking at your data.” P.S. […] The post When you believe in things that you don’t understand appeared first on…

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The Most Important Unexplained Coincidence in Statistics

April 15, 2014
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The exponential family of distributions is important in Statistics because all the common distributions are of this type, and by the Pitman-Koopman theorem, they are exactly the family of distributions which has useful sufficient statistics. By an amaz...

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The Guardian – Big data and open data: what’s what and why does it matter?

April 15, 2014
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The Guardian – Big data and open data: what’s what and why does it matter?

From: http://www.theguardian.com/public-leaders-network/2014/apr/15/big-data-open-data-transform-governmentBoth types of data can transform the world, but when government turns big data into open data it's especially powerfulJoel Gurin, New York U...

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googleVis 0.5.1 released on CRAN

April 15, 2014
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googleVis 0.5.1 released on CRAN

GoogleVis 0.5.1 was released on CRAN yesterday. New Features New functions gvisSankey, gvisAnnotationChart, gvisHistogram,gvisCalendar and gvisTimeline to support the new Google charts of the same names (without 'gvis'). New demo Trendlines showing how...

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Generating tables in LaTeX

April 14, 2014
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Generating tables in LaTeX

Typing tables in LaTeX can get messy, but there are some good tools to simplify the process. One I discovered this week is tablesgenerator.com, a web-based tool for generating LaTeX tables. It also allows the table to saved in other formats including HTML and Markdown. The interface is simple, but it does most things. For complicated tables, some additional formatting may be necessary.     Similar functionality is available via…

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Bayes Pharma 2014 – nearly there…

April 14, 2014
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Bayes Pharma 2014 – nearly there…

We're nearly done with (most of) the preparation for Bayes Pharma 2014. We've received quite a few abstracts for the contributed talks $-$ many different topics but in general very interesting work, I thought.We've managed to secure several sponsorship...

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Causal Inference in Health, Economic and Social Sciences

April 14, 2014
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The programme of the forthcoming UK Causal Inference Meeting "Causal Inference in Health, Economic and Social Sciences" is just out. The short conference will be at the end of the month (28th and 29th of April) at the University of Cambridge.I ind...

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Phil 6334: Notes on Bayesian Inference: Day #11 Slides

April 14, 2014
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Phil 6334: Notes on Bayesian Inference: Day #11 Slides

  A. Spanos Probability/Statistics Lecture Notes 7: An Introduction to Bayesian Inference (4/10/14) Spanos lecture 7: An Introduction to Bayesian Inference from jemille6 Filed under: Bayesian/frequentist, Phil 6334 class material, Statistics

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Transitioning to Stan

April 14, 2014
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Kevin Cartier writes: I’ve been happily using R for a number of years now and recently came across Stan. Looks big and powerful, so I’d like to pick an appropriate project and try it out. I wondered if you could point me to a link or document that goes into the motivation for this tool […] The post Transitioning to Stan appeared first on Statistical Modeling, Causal Inference, and Social…

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Example 2014.4: Hilbert Matrix

April 14, 2014
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Example 2014.4: Hilbert Matrix

Rick Wicklin showed how to make a Hilbert matrix in SAS/IML. Rick has a nice discussion of these matrices and why they might be interesting; the value of H_{r,c} is 1/(r+c-1). We show how to make this matrix in the data step and in R. We also show t...

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On deck this week

April 14, 2014
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Mon: Transitioning to Stan Tues: When you believe in things that you don’t understand Wed: Looking for Bayesian expertise in India, for the purpose of analysis of sarcoma trials Thurs: If you get to the point of asking, just do it. But some difficulties do arise . . . Fri: One-tailed or two-tailed? Sat: Index […] The post On deck this week appeared first on Statistical Modeling, Causal Inference, and…

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Frequentists vs. Bayesians on the Exploding Sun

April 14, 2014
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Frequentists vs. Bayesians on the Exploding Sun

Time for something light.  Check out xkcd.com, "A webcomic of romance, sarcasm, math, and language," written by a literate former NASA engineer.  Really fine stuff.  Thanks to my student M.D. for introducing me to it.  Here's one on...

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Public Universities Should Use Open Source Software

April 14, 2014
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Public Universities Should Use Open Source Software

The Homeless Econometrician: Black Box SoftwareChoosing to go open source is a big deal.  It means that when asking for help or new improvements you are dealing with a highly active and generous user community which enjoys helping instead of a cor...

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