Research design: suggested answers
Level 1 might use a questionnaire (method) to measure post-course satisfaction immediately it ends (cross-sectional design).
Level 2 might use a knowledge questionnaire before and after the course to measure changes in knowledge. It could be done immediately after the course and then again 6 months later (longitudinal design).
Level 3 would use the same method and design as Level 2, measuring stress levels before and after, over time.
Level 4 would take the change scores produced by Level 2 or 3 and use a correlational method to look for relationships between these and changes in outcome scores (e.g. medication error rates) measured before the course and at the same points post-course. Again this is a longitudinal design.