How Much Do Helioseismological Inferences Depend on the Assumed Reference Model?

We investigate systematic uncertainties in determining the profiles of thesolar sound speed, density, and adiabatic index by helioseismologicaltechniques. We find that rms uncertainties-averaged over the sun of ~ 0.2%-0.4%are contributed to the sound speed profile by each of three sources: 1)thechoice of assumed reference model, 2) the width of the inversion kernel, and 3)the measurements errors. The density profile is about an order of magnitudeless well determined by the helioseismological measurements. The profile of theadiabatic index is determined to an accuracy of about 0.2% . We find that evenrelatively crude reference models yield reasonably accurate solar parameters.