Probability Review Questions

Here are the question from the board that I would like everyone to answer for a discussion tomorrow.
  1. How do I find the probability of an event?
  2. What is the sample space of an event?
  3. What is a probability tree?
  4. How do I use a probability tree to work out the probability of several events?
  5. What is an independent event?
  6. When should I use a probability tree and when should I use a probability table?
  7. What is an event and why would I want to work out it's probability?