In this paper, we present the best possible parameters p and q such that the double inequality
$$ M_{p}(a,b)< V(a,b)< M_{q}(a,b) $$
holds for all
$a, b>0$
with
$a\neq b$
, where
$M_{r}(a,b)=[(a^{r}+b^{r})/2]^{1/r}$
(
$r\neq0$
) and
$M_{0}(a,b)= \sqrt {ab}$
is the rth power mean and
$V(a,b)=(a-b)/[\sqrt{2}\sinh^{-1}((a-b)/\sqrt{2ab})]$
is the second Yang mean.
