getStdDeviation method

Implementation

double getStdDeviation(){
  for (int i = partialTimes.length - 1; i > 0; i--) {
  partialTimes[i] = partialTimes[i] - partialTimes[i - 1];
  }
  final average = partialTimes.reduce((a, b) => a + b) / partialTimes.length;
  final sumOfSquares = partialTimes
      .map((v) => pow(v - average, 2))
      .reduce((a, b) => a + b);
  return sumOfSquares/partialTimes.length;
}