function removeOutliers(arr, accessor) {
const values = arr.map(accessor).filter(x => !isNaN(x)).sort((a, b) => a - b);
const q1 = d3.quantile(values, 0.25);
const q3 = d3.quantile(values, 0.75);
const iqr = q3 - q1;
const lower = q1 - 1.5 * iqr;
const upper = q3 + 1.5 * iqr;
return arr.filter(d => {
const value = accessor(d);
return value >= lower && value <= upper;
});
}