code: protected double estimateQuantile(Bucket bucket, double expectedCount, double lastCount) {
  		return bucket.getMin() + (expectedCount - lastCount) * (bucket.getMax() - bucket.getMin()) / bucket.getCount();
  	}
docs: Interpolate quantile located in given Bucket using linear regression.
  <ul>
  <li>Quantile is between {@link Bucket#min} and {@link Bucket#max}</li>
  <li>Expected count is between last count and last count+{@link Bucket#count}</li>
  </ul>
  
  @param bucket Current bucket containing the quantile
  @param expectedCount Searched value
  @param lastCount Value of the bucket lower bound
  @return Compute quantile