\subsection{Ranking}
\label{ranks}

\begin{subfigs}{results_ranks}{Boxplots of the ranking for each visual hand rendering. }[
    Lower is better.
    Pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment: ** is \pinf{0.01} and * is \pinf{0.05}.
  ][
  \item Push task ranking.
  \item Grasp task ranking.
  ]
  \subfig[0.24]{results/Ranks-Push}
  \subfig[0.24]{results/Ranks-Grasp}
\end{subfigs}

\figref{results_ranks} shows the ranking of each visual hand rendering for the Push and Grasp tasks.
%
Friedman tests indicated that both ranking had statistically significant differences (\pinf{0.001}).
%
Pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment were then used on both ranking results (\secref{metrics}):

\begin{itemize}
  \item \textit{Push Ranking}: Occlusion was ranked lower than Contour (\p{0.005}), Skeleton (\p{0.02}), and Mesh (\p{0.03});
    %
    Tips was ranked lower than Skeleton (\p{0.02}).
    %
    This good ranking of the Skeleton rendering for the Push task is consistent with the Push trial results.
  \item \textit{Grasp Ranking}: Occlusion was ranked lower than Contour (\p{0.001}), Skeleton (\p{0.001}), and Mesh (\p{0.007});
    %
    No Hand was ranked lower than Skeleton (\p{0.04}).
    %
    A complete visual hand rendering seemed to be preferred over no visual hand rendering when grasping.
\end{itemize}