"Can you do an example with real numbers?"
BruceZ already gave such an example, in a
post :
Suppose you play three 4-hour sessions. In the first session you win $200. In the second session you win $400. In the third session you lose $300.
According to BruceZ, as he elaborates in his post just above yours in this thread, the average result of those hours you played, ie +$25/hour, is also your hourly Expected Value ("EV").
Before you sat down to play single hand, you may have estimated your EV to be +$10/hour. In other words, you would expect to win $10/hour. I claimed that the use of the term EV or 'expectation' is correct only when referring to such theoretical rather than observed results, but according to BruceZ both uses are equally applicable.