Lambert Adolphe Jacques Quételet (February 22, 1796 – February 17, 1874) was a Belgian astronomer, mathematician, statistician and sociologist. He founded and directed the Brussels Observatory and was influential in introducing statistical methods to the social sciences. Some French-language sources give his last name as Quetelet, with no accent. February 22 is the 53rd day of the year in the Gregorian Calendar. ... Year 1796 (MDCCXCVI) was a leap year starting on Friday (link will display the full calendar) of the Gregorian calendar (or a leap year starting on Monday of the 11-day slower Julian calendar). ... February 17 is the 48th day of the year in the Gregorian calendar. ... 1874 (MDCCCLXXIV) was a common year starting on Thursday (see link for calendar). ... An astronomer or astrophysicist is a person whose area of interest is astronomy or astrophysics. ... Leonhard Euler is considered by many to be one of the greatest mathematicians of all time A mathematician is the person whose primary area of study and research is the field of mathematics. ... Statisticians are mathematicians who work with theoretical and applied statistics in the both the private and public sectors. ... Sociology is the study of the social lives of humans, groups and societies. ... The social sciences are groups of academic disciplines that study the human aspects of the world. ...

Education

Quetelet received a doctorate in mathematics in 1819 from the University of Ghent. Shortly thereafter, the young man set out to convince government officials and private donors to build an astronomical observatory in Brussels; he succeeded in 1828. Euclid, Greek mathematician, 3rd century BC, known today as the father of geometry; shown here in a detail of The School of Athens by Raphael. ... 1819 common year starting on Friday (see link for calendar). ... Ghent University (in Dutch, Universiteit Gent, abbreviated UGent) is one of the two large Flemish universities. ... Nickname: The Capital Of Europe, Comic City City of a 100 Museums[] Map showing the location of Brussels in Belgium Coordinates: Country Belgium Region Brussels-Capital Region Founded 979 Founded (Region) June 18, 1989  - Mayor (Municipality) Freddy Thielemans Area    - City 162 (Region) km²  (62. ... 1828 was a leap year starting on Tuesday (see link for calendar). ...

Sociology

The new science of probability and statistics was mainly used in astronomy at the time, to get a handle on measurement errors with the method of least squares. Quetelet was among the first who attempted to apply it to social science, planning what he called a "social physics". He was keenly aware of the overwhelming complexity of social phenomena, and the many variables that needed measurement. His goal was to understand the statistical laws underlying such phenomena as crime rates, marriage rates or suicide rates. He wanted to explain the values of these variables by other social factors. These ideas were rather controversial among other scientists at the time who held that it contradicted a concept of freedom of choice. Probability is the extent to which something is likely to happen or be the case[1]. Probability theory is used extensively in areas such as statistics, mathematics, science, philosophy to draw conclusions about the likelihood of potential events and the underlying mechanics of complex systems. ... Template:Otherusescccc A graph of a bell curve in a normal distribution showing statistics used in educational assessment, comparing various grading methods. ... In statistics and optimization, the concepts of error and residual are easily confused with each other. ... Least squares or ordinary least squares (OLS) is a mathematical optimization technique which, when given a series of measured data, attempts to find a function which closely approximates the data (a best fit). It attempts to minimize the sum of the squares of the ordinate differences (called residuals) between points...

His most influential book was Sur l'homme et le développement de ses facultés, ou Essai de physique sociale, published in 1835 (In English translation, entitled Treatise on Man). In it, he outlines the project of a social physics and describes his concept of the "average man" (l'homme moyen) who is characterized by the mean values of measured variables that follow a normal distribution. He collected data about many such variables. | Come and take it, slogan of the Texas Revolution 1835 was a common year starting on Thursday (see link for calendar). ... In mathematics, there are numerous methods for calculating the average or central tendency of a list of n numbers. ... The normal distribution, also called Gaussian distribution by scientists (named after Carl Friedrich Gauss due to his rigorous application of the distribution to astronomical data (Havil, 2003)) is a probability distribution of great importance in many fields. ...

Criminology

Quetelet was an influential figure in criminology. Along with Andre-Michel Guerry, he helped to establish the cartographic school and positivist schools of criminology which made extensive use of statistical techniques. Through statistical analysis, Quetelet gained insight into the relationships between crime and other social factors. Among his findings were strong relationships between age and crime, as well as gender and crime. Other influential factors he found included climate, poverty, education, and alcohol consumption, with his research findings published in Of the Development of the Propensity to Crime.^[1] Template:Criminologies Criminology is the scientific study of crime as an individual and social phenomenon. ... André-Michel Guerry (December 24, 1802 – April 9, 1866) was a French lawyer and amateur statistician. ... In criminology, the Positivist School has attempted to find scientific objectivity for the measurement and quantification of criminal behaviour. ... AGE may refer to: advanced glycation endproduct A.G. Edwards, brokerage firm. ... The gender symbols used to denote a male or female organism. ... A boy from an East Cipinang trash dump slum in Jakarta, Indonesia shows his find. ... Functional group of an alcohol molecule. ...

Public health

Principal among these, in terms of influence over later public health agendas, was Quetelet's establishment of a simple measure for classifying people's weight relative to an ideal weight for their height. His proposal, the body mass index (or Quetelet index), has endured with minor variations to the present day. It remains the only widely-recognised raw material for obesity statistics and the policy discussions related to them. Public health is concerned with threats to the overall health of a community based on population health analysis. ... An example of a body mass index chart Body mass index (BMI) or Quetelet Index is a statistical measure of the weight of a person scaled according to height. ... Obesity is a condition in which the natural energy reserve, stored in the fatty tissue of humans and mammals, is increased to a point where it is a risk factor for certain health conditions or increased mortality. ...

Quetelet also founded several statistical journals and societies, and was especially interested in creating international cooperation among statisticians.

Works

• Quetelet, Adolphe (1842). A Treatise on Man and the Development of His Faculties. Scholars Facsimilies & Reprint. ISBN 0-8201-1061-2. 
• Quetelet, Adolphe (1831). The Propensity to Crime. 

References

1. ^ Beirne, Piers (March 1987). "Adolphe Quetelet and the Origins of Positivist Criminology". American Journal of Sociology 92(5): pp. 1140-1169. 

Other references

• Stigler: "Statistics on the Table", Harvard University Press 1999, chapter 2
• Ball, Philip: "Critical Mass: How One Thing Leads to Another", Arrow Books 2005, chapter 3

External links

• O'Connor, John J., and Edmund F. Robertson. "Adolphe Quetelet". MacTutor History of Mathematics archive.