For example: Let’s say that a student is receiving reinforcement once on the of every 5-minutes that he is engaged in the target behavior. In this case, the teacher knows ahead of time that the assignment will take 20-minutes if he stayed on task for the entire time. Because she wants him on a VI schedule of 5:1, she divides the average (5-minutes) into the total number of minutes of behavior (20-minutes in this case). This will give her the number of times she would need to provide reinforcement to the student (4) during that 20-minutes