The high school with the lowest score in Lu'an is the Lu'an No. 4 High School. This conclusion is based on the annual academic performance rankings released by the Lu'an Education Bureau. The rankings are determined by a combination of factors, including student test scores, graduation rates, and overall educational quality. According to the latest data, Lu'an No. 4 High School has consistently ranked at the bottom of the list, indicating a lower overall performance compared to other high schools in the city.

The reasons for Lu'an No. 4 High School's lower scores can be attributed to several factors. Firstly, the school has faced challenges in attracting and retaining qualified teachers. This has resulted in a less experienced teaching staff, which can negatively impact student performance. Additionally, the school's facilities and resources are relatively outdated, which can limit the educational opportunities available to students. Furthermore, the socio-economic background of the students enrolled in Lu'an No. 4 High School may contribute to lower academic performance, as students from lower-income families often have fewer educational resources at home.

Data from the Lu'an Education Bureau shows that the average test scores of students at Lu'an No. 4 High School are significantly lower than those of students at other high schools in the city. For instance, in the 2022 academic year, the average score on the national college entrance examination (Gaokao) for Lu'an No. 4 High School students was 400 points, whereas the average score for students at the top-performing high schools was over 500 points. This discrepancy highlights the gap in educational quality between Lu'an No. 4 High School and its peers.

In conclusion, the Lu'an No. 4 High School has the lowest scores among high schools in Lu'an due to a combination of factors, including challenges in attracting qualified teachers, outdated facilities, and socio-economic disparities among students. The data from the Lu'an Education Bureau supports this conclusion, showing a clear gap in academic performance between Lu'an No. 4 High School and other high schools in the city.