Table 20.

Summary of the central value and all uncertainties in the variables $r_s$ and $R_s$ evaluated at $Q^2=1.9{\text{GeV}}^2$ and $x=0.023$ characterizing the fraction of the strange-quark density in the proton

	$r_s=\frac{s+\overline{s}}{2\overline{d}}$	$R_s=\frac{s+\overline{s}}{\overline{u}+\overline{d}}$
Central value	1.19	1.13
Experimental data	$\pm 0.07$	$\pm 0.05$
Model ($m_b$, $Q_{\min }^2$, $Q_0^2\mathrm{and}{m}_c$)	$\pm 0.02$	$\pm 0.02$
Parameterization	${}_{-0.10}^{+0.02}$	${}_{-0.06}^{+0.01}$
${\mathit{\alpha }}_{\text{S}}$	${}_{-0.01}^{+0.00}$	$\pm 0.01$
EW corrections	$\pm 0.01$	$\pm 0.00$
QCD scales	${}_{-0.10}^{+0.08}$	${}_{-0.07}^{+0.06}$
FEWZ 3.1b2	$+0.10$	$+0.08$
Total uncertainty	${}_{-0.16}^{+0.15}$	$\pm 0.11$