Classical Conditioning Scenario
When a child begins middle school, they are used to the school routine, but they have most likely never encountered a "pop quiz" before. When Julia reaches sixth grade, this applies to her. When her teacher tells the class they're having a pop quiz on what they had learned that week, Julia is called on to answer a question. Confused and under pressure, Julia doesn't understand what's going on and answers incorrectly. This leads to her failing the quiz and impacting her grade. This happens another time or two before she understands the purpose of pop quizes and begins to study more extensively to be ready for them. Despite preparation, she still has trouble responding under pressure, and the anticipation of a possible pop quiz makes her anxious and stressed.
Being called on was at first an unconditioned stimulus, as it had always been part of the middle school routine, but Julia had never encountered it before now. Her natural or unconditioned response was general confusion and answering incorrectly, as she did not understand what was going on. When she learned what pop quizes were for but continued to badly, being called on - or the idea of it - became a conditioned stimulus and her anxiety in anticipation of it became a conditioned response, along with her need to study and keep up in class so, though caught off guard, she wouldn't fail. While anxiety was not an intended response, she achieved the routine that her teacher was looking for, to make sure she and the rest of the class were paying attention to what she was saying. In addition, she showed a similar response when anyone so much as mentioned a test they knew of that was upcoming.