Posts Tagged ‘ randomness ’

What is a Linear Trend, by the way?

January 2, 2017
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What is a Linear Trend, by the way?

I had a very strange discussion on twitter (yes, another one), about regression curves. I think it started with a tweet based on some xkcd picture (just for fun, because it was New Year’s Day) “don’t trust linear regressions” https://t.co/exUCvyRd1G pic.twitter.com/O6rBJfkULa — Arthur Charpentier (@freakonometrics) 1 janvier 2017 There were comments on that picture, by econometricians, mainly about ‘significant’ trends when datasets are very noisy. And I mentioned a graph…

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What if the RNC assigned seating randomly

July 21, 2016
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What if the RNC assigned seating randomly

The punditry has spoken: the most important data question at the Republican Convention is where different states are located. Here is the FiveThirtyEight take on the matter: They crunched some numbers and argue that Trump's margin of victory in the...

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failures and uses of Jaynes’ principle of transformation groups

April 13, 2015
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failures and uses of Jaynes’ principle of transformation groups

This paper by Alon Drory was arXived last week when I was at Columbia. It reassesses Jaynes’ resolution of Bertrand’s paradox, which finds three different probabilities for a given geometric event depending on the underlying σ-algebra (or definition of randomness!). Both Poincaré and Jaynes argued against Bertrand that there was only one acceptable solution under […]

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randomness in coin tosses and last digits of prime numbers

October 7, 2014
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randomness in coin tosses and last digits of prime numbers

A rather intriguing note that was arXived last week: it is essentially one page long and it compares the power law of the frequency range for the Bernoulli experiment with the power law of the frequency range for the distribution of the last digits of the first 10,000 prime numbers to conclude that the power […]

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The odds of a cluster of airplane accidents

August 2, 2014
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The odds of a cluster of airplane accidents

Recently, there have been a lot of airplane accidents. July, 17th 2014, Hrabove, Ukraine, Malaysia Airlines, Boeing 777, fatalities 298 (/298) July, 23rd 2014, Magong, Taiwan, TransAsia Airways, ATR 72-500, fatalities 47 (/58) July, 24th 2014, Aguelhok, Mali, Air Algerie, Mc Donnell Douglas MD-83, fatalities 116 (/116) It is simple to find a lot of datasets about airplane crashes. For instance on http://ntsb.gov/aviationquery. The dataset is nice, with a lot…

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Foundations of Statistical Algorithms [book review]

February 27, 2014
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Foundations of Statistical Algorithms [book review]

There is computational statistics and there is statistical computing. And then there is statistical algorithmic. Not the same thing, by far. This 2014 book by Weihs, Mersman and Ligges, from TU Dortmund, the later being also a member of the R Core team, stands at one end of this wide spectrum of techniques required by […]

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On Wigner’s law (and the semi-circle)

December 17, 2013
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On Wigner’s law (and the semi-circle)

There is something that I love about mathematics: sometimes, you discover – by chance – a law. It has always been there, it might have been well known by some people (specialized in some given field), but you did not know it. And then, you discover it, and you start wondering how comes you never heard about it before… I experienced that feeling this evening, while working on the syallbus for…

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Halloween and candies (a ballot problem)

October 31, 2013
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Halloween and candies (a ballot problem)

This year, for Halloween, a post on candies (I promise, next year I will write another post on zombies). But I don’t want to focus on the kids problems (last year, we tried to minimize their walking distance to collect as much candies as possible, with part 1 and part 2), I want to discuss my own problems. Because usually, the kids wear their costumes, and they go in the streets, they knock on the…

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Random Sequence of Heads and Tails: For R Users

October 10, 2013
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Random Sequence of Heads and Tails: For R Users

Rick Wicklin on the SAS blog made a post today on how to tell if a sequence of coin flips were random.  I figured it was only fair to port the SAS IML code over to R.  Just like Rick Wicklin did in his example this is the Wald-Wolfowitz test for randomness.  I tried to […]

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Once more, superimposing time series creates silly theories

June 10, 2013
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Once more, superimposing time series creates silly theories

After I wrote the post about superimposing two time series to generate fake correlations, there was a lively discussion in the comments about whether a scatter plot would have done better. Here is the promised follow-up post. The contentious issue...

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