Sunday, April 24, 2016

George Waddel Snedecor

George Snedecor (1881-1974) was born in Memphis, TN.  He was the son of a Presbyterian minister, and his family moved through several southern states during his childhood.  He attended Alabama Polytechnic Institute and obtained a dual degree in both Mathematics and Physics. He took his first academic position at the Selma Military Academy, and subsequently went on to teach Mathematics and Greek at Austin College in Sherman, Texas where he met his wife, Gertrude Douglas Croiser. He and his family next moved up north so that George could go back to school. He received a Master’s degree in physics from the University of Michigan in Ann Arbor, MI. With his master’s, he then moved to Ames, Iowa in 1913 to be a professor of Mathematics. It was in Iowa that he began his endeavors in statistics. He began teaching a course called “Mathematical Theory of Statistics”: the first of its kind. He was also among the first academics to integrate statistics with physics and biology. He is most well known for developing the concept of the F distribution and his dedication to teaching non- mathematicians about statistical methods and design.  He is still honored at Iowa State and has a hall named after him.

Established in 1888, the Iowa Agriculture Experiment Station was influenced by Snedecor’s statistical prowess. This was the first lab to apply statistical methods to Agriculture studies. Snedecor was a valuable resource for agricultural experimenters and helped them to design their experiments so that they were able to use statistical analyses and extrapolate their data to future scenarios. Also of note, he worked with Henry Wallace to publish “Correlation and Machine Calculation.” Wallace was one of Snedecor’s peers in statistics and agriculture, who not only developed the first strain of hybrid corn, but also served as the Vice President of the United States under President Franklin Delano Roosevelt.

Invented by John Atanasoff and Clifford Berry, Snedecor used a digital computer for statistical computation. The computer was invented at Iowa State at the aforementioned Agricultural Experiment Station.  At the time, this piece of equipment could only perform simple linear regression. This was the first electronic computer, and it shares three ideas with all modern computers: binary digits, electronic calculations, and separated computation/memory. Snedecor’s lab was the first statistical laboratory to use this technology.
The Mathematics Statistical Service was established in 1927, with Snedecor as its spearhead.  He was an active member of the American Statistics Association, where he was Vice President for a year, and subsequently served a year as President. He was a member of the International Statistical Institute, and was also made an Honorary Fellow of the Royal Statistics Society.

Snedecor is most famous for developing the F distribution, which he named after his close personal friend and colleague, R.A. Fisher. Snedecor first met Fisher during Fisher’s two six-week visits to Iowa State in the summer of 1931 and 1936. Snedecor was one of the first to recognize Fisher’s monumental work on the analysis of variance. Snedecor developed the F distribution in order to improve the ANOVA test and to aid in the its interpretation by including a variance-ratio. Fisher did not necessarily agree with the use of the variance-ratio, and he did not even wish for it to be termed “F” after himself. However, this variance-ratio, the F-distribution, has allowed for the statistical inference of the ANOVA, and today is intimately associated with the ANOVA test. The F distribution is based on the F ratio: the ratio of the effect variance to the error variance. The higher the F value, the more statistically significant is the finding: that is, the effect variance is greater than the error variance.

Snedecor is the author of a very notable book on statistics, that has had eight different editions. Statistical Methods, first published in 1937 is written in conversational style, much like our textbook, Intuitive Biostatistics, by Harvey Motulsky, and has shaped the field of statistics that we know today.

Snedecor was a prominent speaker on statistical methods, and inspired others to do the same. His first student was Gertrude Cox, who has been named the Lady of Statistics. She was the first to graduate with an M.S. in Statistics from Iowa State University. Additionally, Snedecor mentored David Duncan, the inventor of Duncan Multiple Ridge Test.

W.G. Cochran, a pioneer statistician of the same period, encapsulates his life by the following statement:
Our profession owes Snedecor a great debt for his vision in foreseeing the contributions that statistical methods can make in quantities studies, for his book made these methods available to workers with little mathematical training, and his administrative skill in building a major training center and in attracting leaders like Fisher, Yates, Mahalanobis, Kendall, and Neyman to Ames as visitors.


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