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\section{P1}

Let $Y$ be any random variable and $h$ any non-negative
real function.
Show that for all $t>0$,
\[\Pr[h(Y) \geq t] \leq {E[h(Y)] \over t} \]

\section{P2}

Let $X$ a random variable such that $E[X] = \mu$ and $X\leq  2\mu$.
Give an upper bound on $\Pr[X< {\mu\over 2}]$.


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