  In a two-component jet model, the emissions are the sum of the core and
extended emissions: $S^{\rm ob}=S_{\rm core}^{\rm ob}+S_{\rm ext}^{\rm ob}$,
with the core emissions, $S_{\rm core}^{\rm ob}= f S_{\rm ext}^{\rm
ob}\delta^{q}$, being a function of the Doppler factor, $\delta$, the extended
emission, $S_{\rm ext}^{\rm ob}$, jet type dependent factor, $q$, and the ratio
of the core to the extended emissions in the comoving frame, $f$. The $f$ is an
unobservable but important parameter. Following our previous work, we collect
65 blazars with available Doppler factor, $\delta$, superluminal velocity,
$\beta_{app}$, and core-dominance parameter, $R$, calculate the ratio, $f$, and
peform statistical analyses. We find that the ratio, $f$, in BL Lacs is on
average larger than that in FSRQs. We suggest that the difference of the ratio
$f$ between FSRQs and BL Lacs is one of the possible reasons that cause the
difference of other observed properties between them. We also find some
significant correlations between $\log f$ and other parameters, including
intrinsic (de-beamed) peak frequency, $\log \nu _{\rm p}^{\rm in}$, intrinsic
polarization, $\log P^{\rm in}$, and core-dominance parameter, $\log R$, for
the whole sample. In addition, we show that the ratio, $f$, can be estimated by
$R$.
