IQ with comparison

<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
        font: 10px sans-serif;
    }
    .axis path,
    .axis line {
        fill: none;
        stroke: #000;
        shape-rendering: crispEdges;
    }
    .line {
        fill: none;
        stroke: steelblue;
        stroke-width: 1.5px;
    }
  
  	.defaultLine {
    	fill: none;
      stroke: #ccc;
      stroke-width: 1.5px;
  	}
  
  	.defaultArea {
    	fill: rgba(150, 150, 150, 0.9);
  	}
    
    .area {
      fill: steelblue; 
    }
    
  .defaultLabel {
    fill: #ccc;
    font-size: 15px;
  }
  
  .label {
    fill: steelblue;
    font-size: 15px;
    font-weight: bold;
  }
  
  .mean-label {
    font-weight: bold;
    font-size: 12px;
  }
  
  .population-label {
    font-size: 12px;
  }
  
  .mean-container {
    width: 165px;
    padding-left: 413px;
  }
</style>
<div class='mean-container'>
<input id='mean' type='range' min='90' max='110' value='100'>
<br/>
</div>

//setting up empty data array
var defaultData = [];
var data = [];
var dataBelowCutoff = [];
var cutoffCdf = 0;
var mean;
var sd;

getData(); // popuate data

// line chart based on https://bl.ocks.org/mbostock/3883245
var margin = {
        top: 20,
        right: 20,
        bottom: 80,
        left: 50
    },
    width = 960 - margin.left - margin.right,
    height = 450 - margin.top - margin.bottom;

var x = d3.scaleLinear()
    .range([0, width]);

var y = d3.scaleLinear()
    .range([height, 0]);

var xAxis = d3.axisBottom()
    .scale(x);

var yAxis = d3.axisLeft()
    .scale(y);

var svg = d3.select("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

x.domain([40, 160]);
y.domain(d3.extent(data, function(d) {
    return d.p;
}));

svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .call(xAxis);

svg.append("g")
    .attr("class", "y axis")
    .call(yAxis);
    
var path = svg.append("path")
    .datum(data)
    .attr("class", "line")
    .attr("d", line);
  
var areaPath = svg.append('path')
	.attr('class', 'area');

var defaultPath = svg.append('path')
	.datum(data)
 	.attr('class', 'defaultLine')
 	.attr('d', line);
  
var defaultAreaPath = svg.append('path')
	.datum(dataBelowCutoff)
	.attr('class', 'defaultArea')
	.attr("d", area);
  
var defaultTextLabel = svg.append('text')
	.attr('class', 'defaultLabel')
  .attr('x', x(71))
	.attr('y', y(dataBelowCutoff[dataBelowCutoff.length - 1].p / 3))
	.text(d3.format(".1%")(cutoffCdf));

var textLabel = svg.append('text')
	.attr('class', 'label')
	.attr('x', x(71));
  
var numberChildrenLabel = svg.append('text')
	.attr('class', 'label')
	.attr('x', x(71))
	.attr('y', height + 40);
  
var iqLabel = svg.append('text')
	.attr('class', 'label')
	.attr('x', x(71))
	.attr('y', height + 60);
  
var labelGroup = svg.append('g')
	.attr('transform', 'translate(' + x(71) + ',' + (height + 75) + ')');
    
labelGroup.append('text')
	.attr('class', 'population-label')
  .text('in a population of 23.7 million  children');
  
var meanLabel = svg.append('text')
	.attr('class', 'mean-label')
	.attr('y', -10)
	.attr('text-anchor', 'middle');
  
var numberChildrenFormatter = d3.format(',.2r');
var iqFormatter = d3.format('.0f');
  
update();

d3.select('#mean').on('input', function() {
	getData();
  
  update();
});

function getData() {
  mean = parseFloat(document.getElementById('mean').value);
  sd = 15;
  data = [];
  // loop  to populate data array with 
  // probabily - quantile pairs
  for (var i = 40; i < 160; i += 1) {
      data.push({
          "q": i,
          "p": jStat.normal.pdf(i, mean, sd)
      });
  };

dataBelowCutoff = data.slice(0, 31);
  cutoffCdf = jStat.normal.cdf(70, mean, sd);
}
</script>

https://d3js.org/d3.v4.min.js

https://cdn.jsdelivr.net/jstat/latest/jstat.min.js