ageDefaultersChart.js

//d3.extent will give us the min AND max, which makes it easy for us to setup a scale for our x-axis
var ageMinMax = d3.extent(data, function (d) {
    return d['AGE'];
});

ageDefaultersChart
    .width(900)
    .height(250)
    .dimension(ageDefaultersDim)
    .group(ageDefaultersDim.group().reduceSum(dc.pluck('default payment next month'))) //this will choose the attribute for those that defaulted
    .x(d3.scale.linear().domain(ageMinMax)) //setup our x-axis using the previously calculated value
    .elasticY(true) //lets y-axis freely change as filters change
    .elasticX(true)
    .xAxisLabel('Age') //label your axis!
    .yAxisLabel('People Who Defaulted')
    .controlsUseVisibility(true);

$('#ageDefaulters > a').on('click', function (e) {
    ageDefaultersChart.filterAll();
    dc.redrawAll();
    e.preventDefault();
});