public double actualErrorRate() {
    return BloomFilterUtil.actualErrorRate(keyCount, byteSize * 8, hashCount);
  }
Computes the error rate for this Bloom filter, taking into account the actual number of hash
functions and keys inserted. The return value of this function changes as a Bloom filter is
being populated. Used for reporting the actual error rate of compound Bloom filters when
writing them out.
@return error rate for this particular Bloom filter
hbase-server/src/main/java/org/apache/hadoop/hbase/util/BloomFilterChunk.java