Final answer:
Daniel's tendency to attribute his test performance to the teacher's leniency or luck is an example of self-serving bias, which involves attributing successes to internal factors and failures to external ones to protect self-esteem.
Step-by-step explanation:
When Daniel performs well on a test and thinks that his teacher was being lenient or that he was lucky, he is exhibiting what is known as the self-serving bias. This cognitive bias leads people to attribute their successes to internal or dispositional factors while attributing failures to external or situational factors. In Daniel's case, instead of recognizing his ability or hard work as the reason for his good performance, he attributes it to external factors like the teacher's leniency or luck, thereby protecting his self-esteem.