Answer:
Variable ratio
Step-by-step explanation:
In psychology, specifically in operant conditioning, a variable-ratio schedule is a schedule of reinforcement in which a response is reinforced after an unpredictable number of responses.
This schedule results in a high rate of responding since the person doesn't really know when he/she is going to get the reinforcement. (as in the casinos).
Professor Jackson wants his students to complete their reading assignments before classes. He periodically gives them pop quizzes on reading assignments.
To encourage them to complete these assignments he should implement the variable ratio schedule of reinforcement since the students wouldn't know when the next pop quiz is going to be and therefore they should be prepared for them at any time.