Several researchers have observed that, in a wide variety of collections of numerical data, the leading --- or most significant --- decimal digits are not uniformly distributed, but conform to a logarithmic distribution. Of the nine possible values, $latex {D_1=1}&fg=000000$ occurs more than $latex {30\%}&fg=000000$ of the time while $latex {D_1=9}&fg=000000$ is found in less … Continue reading Benford’s Law Revisited
Tag: Statistics
The Improbability Principle and the Seanad Election
A by-election for the Seanad Éireann Dublin University constituency, arising from the election of Ivana Bacik to Dáil Éireann, is in progress. There are seventeen candidates, eight men and nine women. Examining the ballot paper, I immediately noticed an imbalance: the top three candidates, and seven of the top ten, are men. The last six … Continue reading The Improbability Principle and the Seanad Election
How many numbers begin with a 1? More than 30%!
The irregular distribution of the first digits of numbers in data-bases provides a valuable tool for fraud detection. A remarkable rule that applies to many datasets was accidentally discovered by an American physicist, Frank Benford, who described his discovery in a 1938 paper, "The Law of Anomalous Numbers" [TM181 or search for “thatsmaths” at irishtimes.com]. … Continue reading How many numbers begin with a 1? More than 30%!
An English Lady with a Certain Taste
One hundred years ago, an English lady, Dr Muriel Bristol, amazed some leading statisticians by proving that she could determine by taste the order in which the constituents are poured in a cup of tea. One of the statisticians was Ronald Fisher. The other was William Roach, who was to marry Dr Bristol shortly afterwards. … Continue reading An English Lady with a Certain Taste
ToplDice is Markovian
Many problems in probability are solved by assuming independence of separate experiments. When we toss a coin, it is assumed that the outcome does not depend on the results of previous tosses. Similarly, each cast of a die is assumed to be independent of previous casts. However, this assumption is frequently invalid. Draw a card … Continue reading ToplDice is Markovian
Andrey Markov’s Brilliant Ideas are still a Driving Force
Imagine examining the first 20,000 letters of a book, counting frequencies and studying patterns. This is precisely what Andrey Markov did when he analyzed the text of Alexander Pushkin's verse novel Eugene Onegin. This work comprises almost 400 stanzas of iambic tetrameter and is a classic of Russian literature. Markov studied the way vowels and … Continue reading Andrey Markov’s Brilliant Ideas are still a Driving Force
The Improbability Principle
Extremely improbable events are commonplace. “It's an unusual day if nothing unusual happens”. This aphorism encapsulates a characteristic pattern of events called the Improbability Principle. Popularised by statistician Sir David Hand, emeritus professor at Imperial College London, it codifies the paradoxical idea that extremely improbable events happen frequently. [TM112 or search for “thatsmaths” at irishtimes.com]. We … Continue reading The Improbability Principle
The Citizens’ Assembly: Why do 10 Counties have no Members?
Recently, the Irish Government established the Citizens' Assembly, a body of 99 citizens that will consider a number of constitutional issues. The Assembly meets on Saturday to continue its deliberations on the Eighth Amendment to the Constitution, which concerns the ban on abortion. It will report to the Oireachtas (Parliament) on this issue in June … Continue reading The Citizens’ Assembly: Why do 10 Counties have no Members?
Twenty Heads in Succession: How Long will we Wait?
If three flips of a coin produce three heads, there is no surprise. But if 20 successive heads show up, you should be suspicious: the chances of this are less than one in a a million, so it is more likely than not that the coin is unbalanced. Waiting Time for a Single Head On average, … Continue reading Twenty Heads in Succession: How Long will we Wait?
Mathematics Solving Crimes
What use is maths? Why should we learn it? A forensic scientist could answer that virtually all the mathematics we learn at school is used to solve crimes. Forensic science considers physical evidence relating to criminal activity and practitioners need competence in mathematics as well as in the physical, chemical and biological sciences [TM080: search … Continue reading Mathematics Solving Crimes
The Faraday of Statistics
This week, That’s Maths in The Irish Times ( TM044 ) is about the originator of Students t-distribution. In October 2012 a plaque was unveiled at St Patrick's National School, Blackrock, to commemorate William Sealy Gosset, who had lived nearby for 22 years. Sir Ronald Fisher, a giant among statisticians, called Gosset “The Faraday of … Continue reading The Faraday of Statistics
Population Projections
The Population Division of the United Nations marked 31 October 2011 as the "Day of Seven Billion". While that was a publicity gambit, world population is now above this figure and climbing. The global ecosystem is seriously stressed, and climate change is greatly aggravated by the expanding population. Accurate estimates of growth are essential for … Continue reading Population Projections
A Simple Growth Function
Three Styles of Growth Early models of population growth represented the number of people as an exponential function of time, $latex \displaystyle N(t) = N_0 \exp(t/\tau) &fg=000000$ where $latex {\tau}&fg=000000$ is the e-folding time. For every period of length $latex {\tau}&fg=000000$, the population increases by a factor $latex {e\approx 2.7}&fg=000000$. Exponential growth was assumed by … Continue reading A Simple Growth Function
Bayes Rules OK
This week, That's Maths ( TM018 ) deals with the "war" between Bayesians and frequentists, a long-running conflict that has now subsided. It is 250 years since the presentation of Bayes' results to the Royal Society in 1763. The column below was inspired by a book, The Theory that would not Die, by Sharon Bertsch … Continue reading Bayes Rules OK
