code: public Histogram newMaxDiffAreaHistogram(int numBkts) {
  		Map<String, BucketBuilder> initBbs = new HashMap<String, BucketBuilder>();
  		for (String fld : schema.fields()) {
  			initBbs.put(fld, new MaxDiffAreaBucketBuilder(frequencies(fld),
  					null));
  		}
  		return newMaxDiffHistogram(numBkts, initBbs);
  	}
docs: Constructs a histogram with the "MaxDiff(V, A)" buckets for all fields.
  All fields must be numeric.
  
  @param numBkts
  the number of buckets to construct for each field
  @return a "MaxDiff(V, A)" histogram