Quantum Mechanics - Expectation Value

If ψ is a normalized solution of the Schrodinger equation and Q is the operator corresponding to a physical observable x and the quantity ψ*Qψ may be integrated in order to obtain the 

A. Normalization constant for ψ
B. Spatial overlap of Q with ψ
C. Mean value of x
D. Uncertainty in x
E. Time derivative of x

(GR8677 #56)

Solution:

Expectation value: 

• The predicted mean value of the result of an experiment.
• The average value of the measurable quantity Q (observable x) on the state ψ

Answer: C