  Electrical resistivity $\rho(T)$ and specific heat $C(T)$ measurements have
been made on the diluted 4$f^2$ system Y(Pr)Ir$_2$Zn$_{20}$. Both data of
$\rho$ and magnetic specific heat $C_{\rm m}$ per Pr ion are well scaled as a
function of $T/T_{\rm 0}$, where $T_{\rm 0}$ is a characteristic temperature of
non-Fermi liquid (NFL) behaviors. Furthermore, the temperature dependences of
$\rho$ and $C_{\mathrm{m}}/T$ agree with the NFL behaviors predicted by the
two-channel Kondo model for the strong coupling limit. Therefore, we infer that
the observed NFL behaviors result from the single-site quadrupole Kondo effect
due to the hybridization of the 4$f^2$ states with multi-channel conduction
electrons.
