A statistical version of prophet inequalities

Abstract

All classical “prophet inequalities” for independent random variables hold also in the case where only a noise-corrupted version of those variables is observable. That is, if the pairs $(X_1, Z_1),\ldots,(X_n, Z_n)$ are independent with arbitrary, known joint distributions, and only the sequence $Z_1 ,\ldots,Z_n$ is observable, then all prophet inequalities which would 1 n hold if the $X$’s were directly observable still hold, even though the expected $X$-values (i.e., the payoffs) for both the prophet and statistician, will be different. Our model includes, for example, the case when $Z_i=X_i + Y_i$, where the $Y$’s are any sequence of independent random variables.