In a certain year, the city's college entrance examinations for arts and sciences were all students of Zhiyuan Private High School, so many parents concluded that "the quality of Zhiyuan Middle School is higher than the city's key high school-the first high school". Which of the following best refutes these parents' conclusions? ['The appearance of the number one liberal arts college entrance examination is not the only criterion for measuring the level of school teaching.', 'The average college entrance examination score of Zhiyuan Middle School students was much lower than that of a city middle school student that year.', 'Because the teachers of Zhiyuan Middle School are well treated, many teachers leave the city No.1 Middle School to come to Zhiyuan to teach.', 'The students of Zhiyuan Middle School all live in houses, so they spend more time studying at school than City No.1 Middle School.']