This bar chart visualizes average sepal width for three iris species from Fisher’s Iris dataset, with hover interactions to dim non-highlighted bars and a click to decompose a species into raw jittered data points. Built using D3.js 7.8.5, it leverages `d3.csv`, `d3.rollup`, `d3.mean`, `scaleBand`, `scaleLinear`, `scaleOrdinal`, `axisBottom`, and `axisLeft` for aggregation, scaling, and axes. A custom tooltip follows the mouse via SVG `getBoundingClientRect` calculations.