\label{fig:varImpactTrapz} Relative uncertainties of the trapezoidal transit parameters derived from Kepler long-cadence data, as functions of impact parameter \(b\). We have assumed nominal planet parameters \(R_\star = R_\odot\), \(M_\star = M_\odot\), \(P_{orb} = 9.55~\text{days}\), \(e = 0.16\), and \(r = 0.1\). To isolate systematic error in parameter measurement from parameter uncertainty, the relative uncertainties are scaled by the true value of the parameter.