Fixed-Ratio Schedule
With this type of operant conditioning reinforcement schedule, an organism must make a certain number of operant responses (whatever it may be in that experiment) in order to receive reinforcement. For example, if you are conducting a study in which you place a rat on a fixed-ratio 30 schedule (FR-30), and the operant response is pressing the lever, then the rat must press the lever 30 times before it will receive reinforcement. This type of schedule is called fixed because the number of operant responses required remains constant.