So my measurement of a quantum system is an eigenvalue of that operator. And we are not able to predict what eigenvalue we will get, even if we knew the precise state vector before we make our measurement. But QM allows us to calculate the average of all these eigenvalues, if we made an infinite amount of measurements and then took the average. And we call this the expectation value. So the expectation value that we calculate might not even be a possible eigenvalue that we could measure? Im just starting to learn QM. Any input will be much appreciated.