3.3.2 Statistics of quantum operators

1
If the wave function of a one dimensional harmonic oscillator is

\begin{displaymath}
\sqrt{\frac{1}{2}}\psi_0 +
\sqrt{\frac{1}{2}}\psi_1 +
0 \psi_2
\end{displaymath}

where the eigenfunctions have energies $\frac12\hbar\omega$, $\frac32\hbar\omega$, and $\frac52\hbar\omega$, then what is the expectation value of the energy?