code: public double getStatValueAsDouble(T metric, String interval) {
          StatValue statValue = getMonitoredStatValue(metric);
          if (metric.isRateMetric()) {
              //check for DEFAULT can be removed when same check removed from statValueImpl
              if("default".equals(interval)) {
                  interval = DefaultIntervals.ONE_MINUTE.getName();
              }
              double result = statValue.getValueAsLong(interval);
              long duration = IntervalRegistry.getInstance().getInterval(interval).getLength();
              if (duration > 0)
                  result /= duration;
              return result;
          }
          return statValue.getValueAsDouble(interval);
      }
docs: Get value of provided metric for the given interval as double value.
  @param metric metric which value we wanna get
  @param interval the name of the Interval or <code>null</code> to get the absolute value
  @return the current value