fixed interval, ratio & variable interval, ratio

• Fixed Ratio


  You get a free flight on a frequent flyer program after accumulating so many flights.
• Variable Ratio


  Slot machines at a gambling casino often pay out after an average amount of times that the machine is played.
• Fixed Interval


  Checking the oven to see if cookies are done when the cooking time is known (i.e., they won't be done until that time is up).
• Variable Ratio


  Buying lottery tickets
• Continuous


  Herman gets a sticker every time he behaves at the doctor.
• Fixed Interval

  You get a paid vacation after working at a company for 6 months.
• Fixed Ratio


  You are paid on a commission and get paid for every five sales.
• Fixed Interval


  Checking your mail when you know the mailman comes every day at 1 PM.
• Variable Interval


  Melvin gets a break when he has worked for about ten minutes on his math worksheet.
• Variable Ratio


  You are in sales and know that on average, every five people you call will buy your product.