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getting a snack after reading every 30 pages
fixed ratio
a hotel maid takes a 15 minute break after cleaning 10 rooms
fixed ratio
scratch off lottery tickets
variable ratio
slot machines
variable ratio
clicking "get mail" in outlook
variable interval
your teacher gives pop quizzes
variable interval
picking up the paper in the morning after it has been delivered at the same time every day
fixed interval
checking the refrigerator to see if JELLO is ready
variable ratio/interval
checking the mail for a letter from a friend
variable interval
a boxer has to hit his opponent a variable number of times before a knockout
variable ratio
a charitable organization makes an average of 10 phone calls for every donation it receives
fixed ratio
a blueberry picker receives $1 after filling three pint boxes
fixed ratio
a dog receives a treat after it turns around four times
fixed ratio
a person plays the lottery in hopes of winning
variable ratio
a writer sells stories only occasionally
variable interval
metro train/bus schedule
fixed interval
checking the clock as the end of class nears
variable interval
a professional baseball player gets a hit approximately every third time at bat
fixed ratio
a woman asks men at a dance club to dance with her
variable ratio
subway reward card: get XX stamps, get XX free
fixed ratio
when a student graduates, once they earn XX hours they receive their diploma
fixed ratio
a student receives grades at the end of every semester
fixed interval
checking cell phone for text messages when phone is on silent
variable interval
getting a gift on your birthday (what behavior is being reinforced?)
fixed interval
checking the front porch for a newspaper when the deliverer is extremely unpredictable
variable interval