\begin{table}[]
\centering
\rowcolors{2}{lightgray!40}{}
\caption{}
\begin{tabular}{c c c}\rowcolor{lightgray} 
Parameter & NONMEM & Pumas \\ 
$\mu_{Cl}$ & 2.7 & 2.7 \\ 
$\mu_{V}$ & 3.7 & 3.7 \\ 
$\beta_{Cl, CLCR}$ & 7.4 & 7.4 \\ 
$\beta_{V, Weight}$ & 7.2 & 7.2 \\ 
$\beta_{V, Sex}$ & 13.7 & 13.7 \\ 
$\omega^2_{Cl}$ & 20.7 & 20.7 \\ 
$\omega^2_{V}$ & 15.8 & 15.8 \\ 
$a^2$ & 10 & 10 \\ 
$b^2$ & 17 & 17 \\ 
\end{tabular} 
 label{tab:} 
 \end{table}