- This is the average. Going along with your second question you can get a sense of the distribution by looking at the payouts and probabilities in the official rules (https://www.withyotta.com/official-rules)

- It's purely probabilistic so it doesn't need to be tested. It's just random number math.

- Wins are deposited into your Yotta account and are immediately available to withdraw if you'd like

- It's an actual random number generator