A D3.js bar chart displays the average math scores for students grouped by academic department, using data from a CSV file containing individual student records. The chart aggregates the scores per department and visualizes them as blue bars that change to orange on hover. The implementation uses `d3.group` and `d3.mean` to compute averages, with `d3.scaleBand` for the category axis and `d3.scaleLinear` for the score axis. The SVG rendering includes rotated x-axis labels and clearly labeled axes for the department and average math score.