What best describes a fixed ratio schedule?

A fixed ratio schedule is best described as a reinforcement strategy where reinforcement is provided after a specific number of responses have been completed. This means that the individual must perform a set number of tasks or behaviors before receiving a reward. For example, if a person is paid for every five items they produce, they will only receive reinforcement (in the form of payment) after producing five items. This type of schedule tends to create a high rate of response because individuals are motivated to reach the predetermined number of behaviors to receive the reinforcement.

In contrast, other options describe different reinforcement schedules or conditions. Reinforcement based on time refers to a fixed interval schedule, where the reward is given after a specific amount of time has passed, regardless of the number of responses. A schedule that varies widely does not align with the predictable nature of a fixed ratio; this would better describe a variable ratio schedule, where reinforcement is provided after an unpredictable number of responses. Lastly, the absence of reinforcement does not constitute any schedule; thus, stating that no reinforcement is provided does not accurately describe any schedule of reinforcement.