# Statistics

Statistics Blogs

## 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…

## Errors on percentage errors

April 16, 2014
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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…

## A. Spanos: Jerzy Neyman and his Enduring Legacy

April 16, 2014
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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 […]

## Econometric Game, 2014

April 15, 2014
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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...

## 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 […]

## 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…Read more ›

## 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...

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

April 15, 2014
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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...

## Generating tables in LaTeX

April 14, 2014
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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…

## Bayes Pharma 2014 – nearly there…

April 14, 2014
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We're nearly done with (most of) the preparation for Bayes Pharma 2014. We've received quite some abstracts for the contributed talks \$-\$ different topics but in general very interesting work, I thought.We've managed to secure several sponsorship \$-\$ w...