Kettler (1796 ~ 1874) is a Belgian statistician, mathematician and astronomer. Born in a small merchant family in Gant, Belgium. 18 19 graduated from the university of Ghent with excellent results in mathematics, and engaged in mathematics teaching in Athena school in Brussels. 1823 went to Paris, France to study astronomy. 65438-0828 Professor of Brussels University, teaching astronomy, surveying, studying meteorology and statistics. 1834 secretary of Belgian academy of sciences. 184 1 was the chairman of the Belgian central statistical Committee. 185 1 actively prepared for the organization of the international statistical society and served as the chairman of the first international statistical congress. Later, he was elected as a standing member of the Statistics Department of the British Association for the Advancement of Science and an academician of the European National Academy of Sciences.
Kettler is called "the father of modern statistics" and "the father of international statistical conferences" by statisticians. He wrote many books, including 65 kinds of statistics. The most influential ones are: On the Development of Man and His Talents (renamed Social Physics (1835) when it was reprinted, Letters on the Application of Probability Theory to Moral Science and Political Science (1846), Social System and Its Leading Laws (1848) and.
Father of modern statistics
Human statistical practice begins with counting, which exists in primitive society. With the passage of time, human statistical practice activities are becoming more and more abundant. 17th century, "statistics" came into being. The emergence of statistics was originally related to "compiling national reports". As the head of state, ruler and politician, we must understand the income and expenditure of the country, the surplus and shortage of production, the export and import of products economically; Militarily, we must understand the strength of attack and defense; Legally, it is necessary to understand the crime situation in society, and so on. Therefore, it has become a statistical task to compile data, materials and charts about national conditions and national strength in this respect. Therefore, the earliest statistics was also called "national conditions", that is, it mainly studied "national conditions". In the17th century, people who studied this subject were called "national conditions school" in Germany and "political arithmetic school" in Britain. The former pays more attention to the description of materials and the compilation of yearbook, while the latter pays more attention to the application of quantitative analysis methods. However, both schools have their limitations. First, they are still in the primary stage of statistical accounting to a great extent, and can only use simple and rough arithmetic methods to measure and compare social and economic phenomena. Second, they only describe the national strength and national conditions of each country and study social phenomena statically. Third, the static laws of their statistical results are often explained by the will of "God", but they are not regarded as the inherent statistical laws behind social phenomena.
Since the Renaissance, people have noticed that after a lot of gambling activities such as playing cards and dice, there will be some regularity. Probability theory is the earliest product of studying this regularity. Through the research of Pascal in France in the17th century, Bernoulli in Switzerland in the18th century, Mo Affre and Laplacian in France, Bayesian in Britain in the19th century and Gauss in Germany, a classical "probability theory" for studying the regularity of random phenomena has been formed in the19th century. Laplace said: "Because most of the causes of phenomena are unknown to us, or even if we know them, we can't calculate them because the reasons are complicated;" The reason is often the interference of accidental factors or irregular factors, which makes things change in development. Only by long-term and large-scale observation can we get the real development law. Probability theory can study the components that play a role in this development and change, and can express the number of components. "
Due to historical reasons, from 16 to 18 century, the emergence and formation of probability theory had little connection with statistics. Statistics seldom apply probability theory to their own fields. What really combines statistics with probability theory is/kloc-the achievement of kettler in the 9th century. Therefore, people call him "the father of modern statistics".
People think that social phenomena have their own statistical regularity.
18 19 after graduating from kettler university, I mainly engaged in mathematics teaching. 1823, he was sent to Paris by the government to study astronomy. During his study, kettler got acquainted with Laplace, Pinus tabulaeformis, Fourier and other probability theory experts and scholars, and learned a higher level of probability theory knowledge from them. At the same time, he was also influenced by the mechanistic view of nature prevailing in France at that time, especially Laplace's mechanical materialism. From 65438 to 0827, I went to study in London and was exposed to the economic statistics and demographic thinking methods of the political arithmetic school. After returning home, kettler became a professor at the University of Brussels, teaching astronomy and surveying. From 65438 to 0828, he wrote the Handbook of Comprehensive Statistics in Belgium and the Introduction to Probability Calculation. 1829, who helped formulate the Dutch population survey plan. 1829 to 1830 went to Germany, Italy, Switzerland and other countries to engage in geomagnetic investigation and research. In Germany, he met gauss. During his stay abroad, he also came into contact with the actual statistical problems in life insurance business and increased his interest in statistical research. 183 1 year, after Belgium left the Netherlands, kettler participated in the establishment of the new Belgian General Statistics Bureau. In the following five years, he began to engage in statistical research on population and crime.
In this kind of research, kettler found that in the past, people thought that social crimes were individual accidents and overall disorder, but also had certain regularity. Based on the statistical data of Britain, France and Russia, he did a lot of statistical analysis, and found that if we continuously observe the crime figures for several years, such as the number of homicide cases, methods of homicide, forms of crime, conviction ratio and so on. We can see that these figures change in the same range every year, showing a certain regularity.
In addition, kettler also found the same phenomenon when making statistics on human suicide, population, marriage and mental patients. Therefore, kettler confirmed that the seemingly chaotic social phenomenon dominated by contingency has certain regularity as the natural phenomenon. He believes that statistics should not only describe the national conditions of countries and study the static state of social phenomena, but also study the dynamics of social life and the laws behind social phenomena. Kettler's thought laid the foundation for the scientification of modern statistics. He also believes that this regularity behind social phenomena is inherent in society, not "the order created by God"; People can reveal these laws by calculating statistical indicators. Kettler's thoughts have a far-reaching influence on statisticians in later generations.
The regularity of crime statistics reminds kettler of the budget of the judicial department. In 1829, he said, "It can be expected that the same crime will occur in the same sequence every year. The budgets of prisons and courts are similar to the annual income of the country. " 1835, in his book On Human Nature, he said: "In the world, people decide the budgets of prisons, execution grounds and guillotines according to some amazing routine every year. Although people try their best to save this expense, as long as they carefully examine the amount of these expenses, they unfortunately win my prediction every year. " Marx fully affirmed kettler's above achievements: "The Estimation of Possible Crimes published by Mr. kettler in 1829 not only estimated the total number of French criminal acts in the late period of 1830 with amazing accuracy, but also estimated the types of crimes."
Kettler also set out from reality, regardless of the prejudice of the ruling class at that time, and proposed that there was no necessary connection between crime and poverty. According to statistics, he concluded that crime is related to economic prosperity because the number of crimes in the poorest areas is not as much as that in economically developed areas. Kettler's above work shines everywhere with the brilliance of his thought of social statistical regularity, which gives great enlightenment to future generations.
Combine statistics with probability theory.
Statistics became scientific statistics in the modern sense, which originated from the introduction of probability theory, and its founder was kettler. Before 1828, he studied probability theory from famous mathematicians such as Laplace and wrote the book Introduction to Probability Calculation. He knows that in order to find laws in social phenomena, he must use the theory of probability calculation. He said: "In the phenomenon we are going to study, probability theory will replace everything that people name from reality or experience with something scientific."
Since 183 1, kettler has collected a lot of data about human physiological measurement, such as weight, height and chest circumference. After analysis and research, it is considered that these physiological characteristics fluctuate around an average value, showing a normal distribution described in probability theory.
He took the bust of 5738 Scottish soldiers as an example (the chart is abbreviated).
This distribution law is the same as the distribution law of bullets around the target center when shooting, and it is a normal distribution law with the law of large numbers as the main content revealed by probability theory. Kettler has further applied this rule to test the abnormal situation that the height frequency curve of domestic recruits is inconsistent with the theoretical normal distribution curve, and speculated that this may be a problem in the recruitment work. The survey found that several recruitment agencies did cheat from it. Kettler's above statistical work is actually the application of the theory of normal distribution curve and error law in Laplace's probability theory.
Kettler used the method of probability theory to further study a large number of statistical data in social morality, and found the following basic principle: "When we observe most people, people's will will be averaged without leaving any significant traces. The functions of various parts of the will, like all kinds of phenomena restricted by purely accidental reasons, are neutralized or offset. " This is kettler's famous thought of "ordinary people". He believes that "we should not pay attention to the individual, but should regard the individual as a part of the race." Only by removing people's personality can we get rid of all the accidental things that exist between people. In this way, the individual particularities that only play a small role in a large number of phenomena, or have no effect at all, will naturally average up, so that we can grasp the comprehensive results. At the same time, he also believes that we should also study the reasons for the differences in society that deviate from "ordinary people". According to his research, the smaller the deviation between social owners and "ordinary people", the more relaxed the social contradictions. Cultural positive guidance can reduce the deviation between everyone and "ordinary people", thus reducing the occurrence of crimes. Kettler's thought of "ordinary people" has a great influence in history. Marx also used this idea in his book Das Kapital.
This is how kettler combined statistics with probability theory in his research work. He put forward the idea of the law of large numbers for the first time in the field of social science, and established a statistical theory on the basis of the law of large numbers, believing that all social phenomena are also dominated by the law of large numbers. His statistical thought was once popular and still has influence today.
1857, kettler demonstrated the necessity of measuring statistical values by probability method at the third international statistical conference. 1867, at the sixth international statistical congress, he proposed to set up a special Subcommittee to deal with statistical problems directly related to probability theory. Kettler not only introduced the method of probability statistics into social fields such as population, territory, politics, agriculture, industry, commerce and morality, but also introduced the method of probability statistics into natural fields such as astronomy, meteorology, geography, animals and plants. His idea of probability and statistics is the most common method applied to the quantitative study of anything, which is of great significance to the development of statistics in the future.