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Sufficiency and Jensen's inequality for conditional expectations

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Abstract

For finite sets of probability measures, sufficiency is characterized by means of certain positively homogeneous convex functions. The essential tool is a discussion of equality in Jensen's inequality for conditional expectations. In particular, it is shown that characterizations of sufficiency by Csiszár's f-divergence (1963, Publ. Math. Inst. Hung. Acad. Sci. Ser. A, 8, 85–107) and by optimal solutions of a Bayesian decision problem used by Morse and Sacksteder (1966, Ann. Math. Statist., 37, 203–214) can be proved by the same method.

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References

  • Bauer, H. (1968). Wahrscheinlichkeitstheorie und Grundzüge der Maßtheorie, de Gruyter, Berlin-New York.

    MATH  Google Scholar 

  • Csiszár, I. (1963). Eine informationstheoretische Ungleichung und ihre Anwendung auf den Beweis der Ergodizität von Markoffschen Ketten, Publ. Math. Inst. Hung. Acad. Sci. Ser. A, 8, 85–107.

    MATH  Google Scholar 

  • Csiszár, I. (1967). Information-type measures of difference of probability distributions and indirect observations, Studia Sci. Math. Hungar., 2, 299–318.

    MathSciNet  MATH  Google Scholar 

  • Györfi, L. and Nemetz, T. (1977). f-dissimilarity: A general class of separation measures of several probability measures, Colloq. Math. Soc. János Bolyai, 16, 309–321.

    MathSciNet  MATH  Google Scholar 

  • Kozek, A. and Suchanecki, Z. (1980). Multifunctions of faces for conditional expectations of selectors and Jensen's inequality, J. Multivariate Anal., 10, 579–598.

    Article  MathSciNet  Google Scholar 

  • Morse, N. and Sacksteder, R. (1966). Statistical isomorphism, Ann. Math. Statist., 37, 203–214.

    Article  MathSciNet  Google Scholar 

  • Mussmann, D. (1979). Sufficiency and f-divergences, Studia Sci. Math. Hungar., 14, 37–41.

    MathSciNet  MATH  Google Scholar 

  • Pfanzagl, J. (1974a). A characterization of sufficiency by power functions, Metrika, 21, 197–199.

    Article  MathSciNet  Google Scholar 

  • Pfanzagl, J. (1974b). Convexity and conditional expectations, Ann. Probab., 2, 490–494.

    Article  MathSciNet  Google Scholar 

  • Rubin, H. and Wesler, O. (1958). A note on convexity in Euclidean n-space, Proc. Amer. Math. Soc., 9, 522–523.

    MathSciNet  MATH  Google Scholar 

  • Torgersen, E. N. (1976). Comparison of statistical experiments, Scand. J. Statist., 3, 186–208.

    MathSciNet  MATH  Google Scholar 

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Mussmann, D. Sufficiency and Jensen's inequality for conditional expectations. Ann Inst Stat Math 40, 715–726 (1988). https://doi.org/10.1007/BF00049428

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  • DOI: https://doi.org/10.1007/BF00049428

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