var oneMinute = [0,0.5,1,1.5,2];
   var threeMinute = [0,1,2,3,4];
   var tenMinute = [0,2.5,5,7.5,10];


           labels: {
             formatter: function() {
               switch (selectedTimeRange) {
                 case 60:
                     var tickMarks = oneMinute;
                     break;
                 case 180:
                     break;
                 case 300:
                     break;
                 case 600:
                     var tickMarks = tenMinute;
                     break;
                 case 900:
                     break;
                 case 1200:
                     break;
                 case 1800:
                     break;
                 case 3600:
                     break;
                 case 3600:
                     break;
               }
               return tickMarks;

              }
           }