Udny Yule

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This article is about the statistician. For the Scottish businessman, see George Yule.

George Udny Yule (February 18, 1871 – June 26, 1951) was a Scottish statistician. Yule made important contributions to the theory and practice of correlation, regression, and association, as well as to time series analysis. The Yule distribution, a discrete power law, is named after him.

[edit] Biography

George Udny Yule, or Udny Yule, as he was usually called, was born in Scotland on February 18, 1871 into a family of administrators and scholars. His uncle was the noted orientalist, Sir Henry Yule. Udny Yule was educated at Winchester College and at University College London where he read engineering. After a year in Bonn doing research in experimental physics under Heinrich Rudolf Hertz, Yule returned to University College in 1893 to work as a demonstrator for Karl Pearson, one of his former teachers. Pearson was beginning to work in statistics and Yule followed him into this new field. Yule progressed to an assistant professorship but he left in 1899 to a better-paid position as secretary to an examination board. He continued to publish articles and also a very influential textbook, Introduction to the Theory of Statistics (1911); his book was based on the lectures he gave as the Newmarch lecturer at University College. In 1912 Yule moved to Cambridge University to a new created Lectureship in Statistics and he remained in Cambridge for the rest of his life. During the First World War Yule worked for the army and then for the Ministry of Food. A heart attack in 1931 left him a semi-invalid and led to his early retirement. His flow of publications almost ceased but, in the 1940s he found new interests, one of which led to a book, The Statistical Study of Literary Vocabulary. Udny Yule died in Cambridge on June 26, 1951.

Yule’s first paper on statistics appeared in 1895, "On the Correlation of Total Pauperism with Proportion of Out-relief". Yule was interested in applying statistical techniques to social problems and he quickly became a member of the (Royal) Statistical Society. For many years the only members interested in mathematical statistics were Yule, Edgeworth and Bowley. In 1897–99 Yule wrote important papers on the theory of correlation and regression (linear regression), and after 1900 he worked on a parallel theory of association. His approach to association was quite different from Pearson’s and relations between them deteriorated. Yule had broad interests and his collaborators included the agricultural meteorologist R. H. Hooker, the medical statistician Major Greenwood and the agricultural scientist Sir Frank Engledow. Yule’s sympathy towards the newly rediscovered Mendelian theory of genetics led to several papers. In the 1920s he wrote three influential papers on time series analysis, "On the time-correlation problem" (1921), a critique of the variate difference method, "Why Do We Sometimes Get Nonsense Correlations between Time-series?" (1926), an investigation of a form of spurious correlation, and "On a Method of Investigating Periodicities in Disturbed Series, with Special Reference to Wolfer's Sunspot Numbers" (1927), which used an autoregressive model to model the sunspot time series instead of the established periodogram method of Schuster. Although Yule taught at Cambridge for twenty years, he seems to have had little impact on the development of statistics there. M. S. Bartlett recalled him as a "mentor" but his famous association with Maurice Kendall, who revised the Introduction to the Theory of Statistics, only came about after Kendall had graduated.

[edit] Selected works

• G. Udny Yule, "On the Significance of Bravais' Formulæ for Regression, &c, in the case of Skew Correlation", Proceedings of the Royal Society of London, Vol. 60 (1896–1897), pp. 477–489.
• G. Udny Yule, "On the Association of Attributes in Statistics", Philosophical Transactions of the Royal Society of London, Ser. A, Vol. 194 (1900), pp. 257–319.
• G. Udny Yule, "On the Theory of Correlation for any Number of Variables, Treated by a New System of Notation", Proceedings of the Royal Society of London, Vol. 79 (1907), pp. 182–193.
• G. Udny Yule Introduction to the Theory of Statistics London Griffin 1911.
• G. Udny Yule, "A Mathematical Theory of Evolution, based on the Conclusions of Dr. J. C. Willis, F.R.S.", Philosophical Transactions of the Royal Society of London, Ser. B, Vol. 213 (1925), pp. 21–87.
• G. Udny Yule, "On a Method of Investigating Periodicities in Disturbed Series, with Special Reference to Wolfer's Sunspot Numbers", Philosophical Transactions of the Royal Society of London, Ser. A, Vol. 226 (1927), pp. 267–298.

[edit] External links

• Royal Society citation
• O'Connor, John J., and Edmund F. Robertson. "Udny Yule". MacTutor History of Mathematics archive.
• George Udny Yule: Statistical Scientist