getInitializedAverage
  = function getInitializedAverage(data) {
    return _.reduce(data, (prev, a, dataKey) => {
      // create a first-level object of the key
      prev[dataKey] = {};

      _.each(data[dataKey], (b, dataMetricKey) => {
        // the metrics are properties inside this object
        prev[dataKey][dataMetricKey] = 0;
      });

      return prev;
    }, {});
  }
Given a metric data object, construct an initialized average.

@param {Object} data
The metric data received.

@returns {Object}
The initialized average object is returned.