ms. lee has decided to use an incentive system to improve behavior in her 5th grade class, which has become noisy, rowdy, and frequently off-task. ms. lee tells her students that she will give each of them a card to keep at their desks and that each day that they do not yell, leave their seats without permission, or push and shove each other while entering the room; they will each earn 5 points. however, whenever they engage in one of these behaviors, they will lose one point. students who accumulate 15 points per week will be allowed to participate in special friday activities such as viewing a movie, a popcorn party, or free time activity. an advantage of ms. lee's system is that:
