Lottery tickets encourage patrons to continue playing by giving them periodic rewards after an unpredictable number of ticket purchases. This scenario describes which schedule of reinforcement?

A fixed-ratio schedule delivers rewards after a set number of responses, such as receiving a prize after every 10 tickets purchased. This predictability can lead to a pause in behavior after a reward is received, which does not align with the unpredictability described in the lottery scenario.

In a fixed-interval schedule, rewards are given after a specific amount of time has passed, such as receiving a prize every week regardless of the number of tickets purchased. This time-based reward system does not reflect the behavior of lottery ticket purchasers, who receive rewards based on the number of tickets purchased rather than time.

A variable-interval schedule provides rewards after unpredictable time intervals, such as receiving a prize at random times regardless of responses. While this schedule maintains interest, it differs from the variable-ratio approach, as the lottery rewards are based on the number of ticket purchases rather than the passage of time.