Geometric mean efficiency (E) is not revealed by serial dilution-based determinations of Ψ. Symbols indicate 219 individual samples, from 28 dilution experiments involving 5 different amplicons. Y-axis error bars are the standard deviations of Ψ (propagated from the slope variance of each experimental c
graph); x-axis error bars are standard deviations of E = (A
)1/Cq where A
has a known a posteriori error of 8% (from variance in qPCR instrument calibration slopes), and A
has an a priori error of 10% (from known precision of pipetting and dilution). Dashed diagonal line: Linear regression correlation of Ψ vs. E (R2 = 0.54). Solid diagonal line: Reference along which Ψ = E.