Barley Dot Plot with Wild Lines

<!DOCTYPE html>
<meta charset="utf-8">

.axis text {
    font-size: 12px;
    fill: #777;
  }

.axis path {
    display: none;
  }

.axis line {
    stroke-width:1px;
    stroke: #ccc;
    stroke-dasharray: 2px 2px;
  }

.yearOne {
    fill: none;
    stroke-width: 1px;
    stroke: red;
  }

</style>

var xScale = d3.scale.linear()
   .range([0, width]);

var yScale = d3.scale.ordinal()
   .rangePoints([height, 0]);

var xAxis = d3.svg.axis()
   .scale(xScale)
   .tickSize(-height)
   .tickPadding(8)
   .orient("bottom");

var yAxis = d3.svg.axis()
   .scale(yScale)
   .tickSize(-width)
   .tickPadding(8)
   .orient("left");

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

d3.tsv("barley.tsv", ready)

function ready(error, data) {

if (error) return console.warn(error);

var sampleData = data.filter(function(d) { return d.site == 'Morris'; })
 var barleyYields = data.map(function(d) { return d.yield;})
 var maxYields = d3.max(barleyYields)
 var minYields = d3.min(barleyYields)

xScale.domain([minYields, maxYields]);
yScale.domain(d3.set(sampleData.map(function(d) { return d.variety; })).values());

svg.append("g")
 .attr("class","y axis")
 // .attr("transform","translate(0," + height + ")")
 .call(yAxis);

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

circleGroup.append("circle")
    .attr("r", 3);

var yearOneGroup = data.filter(function(d) { return d.year == '1931'; })
  var yearTwoGroup = data.filter(function(d) { return d.year == '1932'; })
  console.log(yearOneGroup)
  console.log(yearOneGroup)

// begin of drawing lines
  var line = d3.svg.line()
      .x(function(data){
        console.log(data)
        return xScale(data.yield);})
      .y(function(data){
        console.log(data)
        return yScale(data.variety);})
        .interpolate("linear");

svg.append("path")
      .attr("d", function(d) { return line(sampleData)})
      .attr("transform", "translate(0,0)")
      .style("stroke-width", 2)
              .style("stroke", "steelblue")
              .style("fill", "none");
  // end of drawing lines
 
}

</script>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js