Table 1.

Syringe volume errors produced by SP, WA, and PolyLS methods of pneumotachograph calibration

	Entire Data Set		Testing Data Set
Method	Average, %	CI95%	Average, %	CI95%
SP	0.29*†	–0.39 to 1.00	0.29*†	–0.46 to 0.97
WA	0.03	–0.88 to 0.62	0.03†	–1.02 to 0.61
PolyLS	0.01	–1.04 to 0.47	0.01	–1.15 to 0.50

Volume errors are expressed as % of 3 liters. CI_95%, 95th percentile confidence interval of volume errors; PolyLS, polynomial least squares; SP, syringe potentiometer; WA, weighted averaging. Note: The CI_95% of volume errors for the 3 methods all lie within the American Thoracic Society/European Respiratory Society-recommended error margin of ±3.50%.

^*Significantly different from WA method, P < 0.05.

^†Significantly different from PolyLS method, P < 0.05.