Suppose we have three non-negative random variables $X,Y,Z$, they may be dependent and they satisfy $Z\geq\min\{X,Y\}$. Now we know that there exists a constant $A$ such that $E(X)\geq A, E(Y)\geq A$. Is it true that $E(Z)\geq A$?
2026-03-28 10:17:35.1774693055
Switching integration and minimization for positive random variables?
43 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail At
2
No. Let $X$ be $1$ with probability $1/2$ and $0$ otherwise (i.e., a fair coin), $Y = 1-X$, and $Z = \min(X,Y) = 0$. Then $E(X) = E(Y) = 1/2$, but $E(Z) = 0$.