Operant shaping is often used in training various animals to perform tricks with hand signals being used to indicate which trick that the animal is to perform and food treats then being used as reinforcers. Thus, the trainer’s hand signals are serving as

Dr. williams conducted a survey in the mall, measuring the shopping habits of people ages 15, 25, 35, 45, and 55, with 10 people in each group. which of the following best describes her study? an experiment a cross-sectional study a case study a longitudinal study a double-blind study