Conditions and Variables - Quizzing

I am relatively new to e-learning, course creation, etc. etc.  Using Storyline, I am working on a quiz where respondents must get 4 out of 6 questions correct.  If they don't, they have to retake the quiz.

I am guessing that there is a way to do this using conditions and variables.  Does anyone know of any great tutorials out there demonstrating this function or have experience setting up this type of quiz?  

Any guidance is greatly appreciated - thank you!