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Stochastic ordering results on the duration of the gambler’s ruin game

Published online by Cambridge University Press:  06 October 2023

Shoou-Ren Hsiau*
Affiliation:
National Changhua University of Education
Yi-Ching Yao*
Affiliation:
Academia Sinica
*
*Postal address: Department of Mathematics, National Changhua University of Education, No. 1, Jin-De Road, Changhua 500, Taiwan, R.O.C. Email: srhsiau@cc.ncue.edu.tw
**Postal address: Institute of Statistical Science, Academia Sinica, No. 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan, R.O.C. Email: yao@stat.sinica.edu.tw

Abstract

In the classical gambler’s ruin problem, the gambler plays an adversary with initial capitals z and $a-z$, respectively, where $a>0$ and $0< z < a$ are integers. At each round, the gambler wins or loses a dollar with probabilities p and $1-p$. The game continues until one of the two players is ruined. For even a and $0<z\leq {a}/{2}$, the family of distributions of the duration (total number of rounds) of the game indexed by $p \in [0,{\frac{1}{2}}]$ is shown to have monotone (increasing) likelihood ratio, while for ${a}/{2} \leq z<a$, the family of distributions of the duration indexed by $p \in [{\frac{1}{2}}, 1]$ has monotone (decreasing) likelihood ratio. In particular, for $z={a}/{2}$, in terms of the likelihood ratio order, the distribution of the duration is maximized over $p \in [0,1]$ by $p={\frac{1}{2}}$. The case of odd a is also considered in terms of the usual stochastic order. Furthermore, as a limit, the first exit time of Brownian motion is briefly discussed.

Type
Original Article
Copyright
© The Author(s), 2023. Published by Cambridge University Press on behalf of Applied Probability Trust

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References

Abrahams, J. (1986). A survey of recent progress on level-crossing problems for random processes. In Communications and Networks: A Survey of Recent Advances, eds. Blake, I. F. and Poor, H. V.. Springer, New York, pp. 6–25.CrossRefGoogle Scholar
Blake, I. F. and Lindsey, W. C. (1973). Level-crossing problems for random processes. IEEE Trans. Inf. Theory 19, 295315.CrossRefGoogle Scholar
Darling, D. A. and Siegert, A. J. F. (1953). The first passage problem for a continuous Markov process. Ann. Math. Statist. 24, 624639.CrossRefGoogle Scholar
Feller, W. (1968). An Introduction to Probability Theory and its Applications, Vol. 1, 3rd edn. John Wiley, New York.Google Scholar
Feller, W. (1971). An Introduction to Probability Theory and its Applications, Vol. 2, 2nd edn. John Wiley, New York.Google Scholar
Karlin, S. and Rubin, H. (1956). The theory of decision procedures for distributions with monotone likelihood ratio. Ann. Math. Statist. 27, 272299.CrossRefGoogle Scholar
Karlin, S. and Taylor, H. M. (1981). A Second Course in Stochastic Processes. Academic Press, New York.Google Scholar
Peköz, E. A. and Ross, S. M. (2022). Fair gambler’s ruin stochastically maximizes playing time. Adv. Appl. Prob. 54, 656659.CrossRefGoogle Scholar
Privault, N. (2018). Understanding Markov Chains: Examples and Applications, 2nd edn. Springer, Singapore.CrossRefGoogle Scholar
Shaked, M. and Shanthikumar, J. G. (2007). Stochastic Orders. Springer, New York.CrossRefGoogle Scholar