waveform in prototype functions?

I'm receiving negative values when attempting to use this code:

TempSensor.prototype.getTempValue = function () {
  var p = this.aPort; //<-- equals A0 

  var w = new Waveform(128/* your buffer size */,{doubleBuffer:false, bits:16});
  var first = true;

      var myarr = w.buffer;
      myarr.sort();
      // cut off first and last 2 elements
      var view = new Uint16Array(myarr.buffer, 2/*sizeof(uint16)*/*2, myarr.length-4);
      var vOut = E.getAnalogVRef() * E.sum(view)/(view.length*65536); // if you attached VOUT to Ao
      var vZero = 0.4;
      var tCoeff = 19.5 / 1000;
      var tempinc = (vOut - vZero) / tCoeff;
      var tempinf = tempinc * (9 / 5) + 32;
      console.log("Temp in C: " + tempinc);
      console.log("Temp in F: " + tempinf);
      //console.log(E.sum(view)/(view.length*65536));

    w.startInput(p,2000 /* Samples per second */);

};