How to make this expected value symbol?

Question

I'd like to know how to make in mathmode this fat 'E' as a symbol for expected value?

Answer 1

Perhaps you need

\mathbf{E}. 

Does this solve?

 \documentclass{article}  
 \begin{document}
 \[ \mathbf{E}(\xi)=\int_Z\xi d\rho \]
 \end{document}