Enhance your understanding of quasi-experimental designs

Enhance your understanding of quasi-experimental designs.  Evaluate an example of the appropriate use of this methodology, mainly as it might pertain to a counselling environment.  The example can be one you find in the literature or one you make up. Let's say that a professor offers the class an extra five points on their final exam if they participate in a study.  The professor has 500 students in the course.  What would make this an experimental study as compared to a quasi-experimental study?  Reference should be within 10 years

Goodwin, K. A., & Goodwin, C. J. (2017). Research in psychology: Methods and designs (8th ed.). Hoboken, NJ: John Wiley & Sons.