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What Does a Random Contingency Table Look Like?

Published online by Cambridge University Press:  12 February 2010

ALEXANDER BARVINOK*
Affiliation:
Department of Mathematics, University of Michigan, Ann Arbor, MI 48109-1043, USA (e-mail: [email protected])

Abstract

Let R = (r1, . . ., rm) and C = (c1, . . ., cn) be positive integer vectors such that r1 + ⋯ + rm = c1 + ⋯ + cn. We consider the set Σ(R, C) of non-negative m × n integer matrices (contingency tables) with row sums R and column sums C as a finite probability space with the uniform measure. We prove that a random table D ∈ Σ(R, C) is close with high probability to a particular matrix (‘typical table’) Z defined as follows. We let g(x) = (x + 1)ln(x + 1) − x ln x for x ≥ 0 and let g(X) = ∑i,jg(xij) for a non-negative matrix X = (xij). Then g(X) is strictly concave and attains its maximum on the polytope of non-negative m × n matrices X with row sums R and column sums C at a unique point, which we call the typical table Z.

Type
Paper
Copyright
Copyright © Cambridge University Press 2010

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References

[1]Barvinok, A. (2002) A Course in Convexity, Vol. 54 of Graduate Studies in Mathematics, AMS, Providence, RI.CrossRefGoogle Scholar
[2]Barvinok, A. (2009) On the number of matrices and a random matrix with prescribed row and column sums and 0–1 entries. Adv. Math., doi:10.1016/j.aim.2009.12.001.CrossRefGoogle Scholar
[3]Barvinok, A. (2009) Asymptotic estimates for the number of contingency tables, integer flows, and volumes of transportation polytopes. Internat. Math. Research Notices 2009 348385.CrossRefGoogle Scholar
[4]Barvinok, A. and Hartigan, J. A. (2009) Maximum entropy Gaussian approximation for the number of integer points and volumes of polytopes. Preprint arXiv:0903.5223. Adv. in Appl. Math., to appear.CrossRefGoogle Scholar
[5]Barvinok, A., Luria, Z., Samorodnitsky, A. and Yong, A. (2010) An approximation algorithm for counting contingency tables. Random Struct. Algorithms, doi:10.1002/rsa.20301.CrossRefGoogle Scholar
[6]Cryan, M., Dyer, M., Goldberg, L. A., Jerrum, M. and Martin, R. (2006) Rapidly mixing Markov chains for sampling contingency tables with a constant number of rows. SIAM J. Comput. 36 247278.CrossRefGoogle Scholar
[7]Diaconis, P. and Efron, B. (1985) Testing for independence in a two-way table: New interpretations of the chi-square statistic. With discussions and with a reply by the authors. Ann. Statist. 13 845913.Google Scholar
[8]Diaconis, P. and Gangolli, A. (1995) Rectangular arrays with fixed margins. In Discrete Probability and Algorithms: Minneapolis 1993, Vol. 72 of The IMA Volumes in Mathematics and its Applications, Springer, New York, pp. 1541.CrossRefGoogle Scholar
[9]Dyer, M., Kannan, R. and Mount, J. (1997) Sampling contingency tables. Random Struct. Algorithms 10 487506.3.0.CO;2-Q>CrossRefGoogle Scholar
[10]Good, I. J. (1963) Maximum entropy for hypothesis formulation, especially for multidimensional contingency tables. Ann. Math. Statist. 34 911934.CrossRefGoogle Scholar
[11]Greenhill, C. and McKay, B. D. (2008) Asymptotic enumeration of sparse nonnegative integer matrices with specified row and column sums. Adv. Appl. Math. 41 459481.CrossRefGoogle Scholar
[12]Ledoux, M. (2001) The Concentration of Measure Phenomenon, Vol. 89 of Mathematical Surveys and Monographs, AMS, Providence, RI.Google Scholar
[13]O'Neil, P. E. (1969) Asymptotics and random matrices with row-sum and column-sum restrictions. Bull. Amer. Math. Soc. 75 12761282.CrossRefGoogle Scholar
[14]Nesterov, Y. and Nemirovskii, A. (1994) Interior-Point Polynomial Algorithms in Convex Programming, Vol. 13 of SIAM Studies in Applied Mathematics, SIAM, Philadelphia, PA.CrossRefGoogle Scholar