Solution
= Solution
For a nonnegative integer-valued <random variable>, $\mathbf1_{\{X>0\}}\leq X$ pointwise. Taking <expectations> gives
$$
\boxed{\mathbb P(X>0)\leq\mathbb E X}.
$$
This is the indicator form of the <Markov inequality>.
= Solution
For a nonnegative integer-valued <random variable>, $\mathbf1_{\{X>0\}}\leq X$ pointwise. Taking <expectations> gives
$$
\boxed{\mathbb P(X>0)\leq\mathbb E X}.
$$
This is the indicator form of the <Markov inequality>.