with the selection?
      var dataFilter = data.map(function(d){return {time: d.time, value:d[selectedGroup]} })

      // Give these new data to update line
      line
          .datum(dataFilter)
          .transition()
          .duration(1000)
          .attr("d", d3.line()
            .x(function(d) { return x(+d.time) })
            .y(function(d) { return y(+d.value) })
          )
          .attr("stroke", function(d){ return myColor(selectedGroup) })
    }

    // When the button is changed, run th