How to add trend line to high charts

Question

This is the high chart graph code.

Answer 1

Numerous problems.

1.) You didn't really integrate the regresssion code into your plot, you just cut/pasted from the example and are over-drawing your plot. You need to add the regression line as a second series to your plot:

        series: [{
            name: 'RNA - CP ( Radio Network Availability - Customer Perceived)',
            data: sourceData
        },{
            type: 'line',
            marker: { enabled: false },
            /* function returns data for trend-line */
            data: (function() {
              return fitData(sourceData).data;
            })()
        }]

2.) This is not valid javascript:

 var sourceData = [
      [18-Jul-14, 99.75], [19-Jul-14, 99.77],
      [20-Jul-14, 99.78], [21-Jul-14, 99.84],
      [22-Jul-14, 99.82], [23-Jul-14, 99.82],
      [24-Jul-14, 99.76], [25-Jul-14, 99.78],
      [26-Jul-14, 99.8], [27-Jul-14, 99.65],
      [28-Jul-14, 99.94], [29-Jul-14, 99.8]
  ];

Those are strings and they aren't quoted. Regardless, strings won't cut it for the regression, it needs numbers. Since your dates are really categories, just use:

 var sourceData = [
      [0, 99.75], [1, 99.77],
      [2, 99.78], [3, 99.84],
      [4, 99.82], [5, 99.82],
      [6, 99.76], [7, 99.78],
      [8, 99.8], [9, 99.65],
      [10, 99.94], [11, 99.8]
  ];

3.) Your series name is way too long for a right side legend (it squished the plot). In my example I moved it to the bottom.

Here's a example putting all this together.