Is there a way to define as a new operator the mathematical expectation.
Say we call it $\mathrm{M}$ as in the old Mir (russian books).
Wa should have
$\mathrm{M}(kX) = k\mathrm{M}(X)$
$\mathrm{M}(X \pm Y) = \mathrm{M}(X)\pm \mathrm{M}(Y)$
and as a résult
$\mathrm{M}(X -\mathrm{M}X)^2 =\mathrm{M}(X^2)- \mathrm{M}(X)^2$
$\mathrm{M}(aX^2 +bX + c) = a\mathrm{M}(X^2) +b\mathrm{M}(X) + c$
and so on for all polynomial ?