Welcome back. In the next several lessons,you’re going to learn about back-testing, which is how quantum simulate as rigorously as possible. What would have happened if a trading strategy was deployed in production over a historical period, in order to try to understand how it might perform in the future? As we mentioned earlier in the course, back-testing is the last thing you’ll do when researching and testing a strategy. As you can probably guess, there are lots of important subtle considerations you need to keep in mind, in order to make this simulation useful. Let’s keep going to learn the principles of back-testing.