Table 3. Sample size calculations to detect significant change in nasal potential difference if using the ferret model.

True Difference in PD (mV)	% Difference	Sample size to attain 80% power	Sample size to attain 90% power
2.7	20	31 pairs	41 pairs
4.1	30	15 pairs	19 pairs
5.5	40	9 pairs	12 pairs
6.8	50	7 pairs	8 pairs