Does the Selection of a Quiet Region Influence the Local Helioseismic Inferences?

We apply the ring-diagram technique to high resolution Dopplergrams in order to estimate the variation in oscillation mode parameters between active and quiet regions. We demonstrate that the difference in mode parameters between two quiet regions can be as large as those between a pair of active and quiet region. This leads us to conclude that the results derived on the basis of a single quiet region could be biased.