Q:

Numbered list inside a table cell

How can I insert a numbered list inside a table cell?
I want to show a comparison between two different procedures and how they alter a set of sequences. 

A:

You can use either a p{} type column or just insert parboxes around.
Option 1:

\documentclass{article}
\usepackage{booktabs}

\begin{document}
    \begin{tabular}{p{.45\textwidth}p{.45\textwidth}}
        \toprule Head & Head\\\midrule
        \begin{enumerate}
            \item Test
            \item Second
        \end{enumerate} & \begin{enumerate}
            \item Test
            \item Second
            \item Third
        \end{enumerate}\\\bottomrule
    \end{tabular}
\end{document}

Option 2:

\documentclass{article}
\usepackage{booktabs}

\begin{document}
    \begin{tabular}{ll}
        \toprule Head & Head\\\midrule
        \parbox{.45\textwidth}{\begin{enumerate}
            \item Test
            \item Second
        \end{enumerate}} & \parbox{.45\textwidth}{\begin{enumerate}
            \item Test
            \item Second
            \item Third
        \end{enumerate}}\\\bottomrule
    \end{tabular}
\end{document}

A:

Here are some improvements, with tabularx,enumitem and makecell:
\documentclass{article}
\usepackage{booktabs}
\usepackage{enumitem}
\usepackage{tabularx, makecell}%
\renewcommand\theadfont{\normalsize\bfseries}
        \usepackage{etoolbox} %
        \AtBeginEnvironment{tabularx}{\setlist[enumerate, 1]{wide, leftmargin=*, itemsep=0pt, before=\vspace{-\dimexpr\baselineskip +2 \partopsep}, after=\vspace{-\baselineskip}}}

\begin{document}
    \begin{tabularx}{\linewidth}{XX}
        \toprule %
        \thead{Head} & \thead{Head}\\%
        \cmidrule[\lightrulewidth](lr){1-2}
        \begin{enumerate}
            \item Test
            \item Second
        \end{enumerate} & \begin{enumerate}%
            \item Test
            \item Second
            \item Third
        \end{enumerate}\\%
        \bottomrule
    \end{tabularx}

\end{document} 

