\documentclass[varwidth=598pt]{standalone}

\usepackage{booktabs} % professional-quality tables
\usepackage{multirow} % multi-row cells in tables
\usepackage{colortbl} % color for tables (\cellcolor, \rowcolor)
\usepackage[table]{xcolor} % enhanced colors for tables
\usepackage{array} % more flexible column formats (often used)
\usepackage{tabularx} % for tables with auto-stretch columns (if used)
\usepackage{graphicx} % for images in tables or figure/table floats
\usepackage{amssymb} % math symbols
\usepackage{amsmath} % math environments
\usepackage{soul} % highlighting (used for colored text/cells)
\usepackage[normalem]{ulem} % underlining, strikethroughs
\usepackage[T1]{fontenc} % font encoding
\usepackage[utf8]{inputenc}% input encoding (legacy, fine for pdflatex)
\usepackage{microtype} % better text appearance
\usepackage{hyperref} % hyperlinks
\usepackage{textcomp} % for extra symbols
\usepackage{enumitem} % for compact lists (if used in table notes)
\usepackage{adjustbox}
\usepackage{tabu}
\usepackage{pifont} % http://ctan.org/pkg/pifont
\usepackage{bbding} % \XSolidBrush
\usepackage{makecell}

\begingroup
\makeatletter
\renewcommand{\fnum@table}{}%
\long\def\@makecaption#1#2{%
\vskip\abovecaptionskip
\centering #2\par
\vskip\belowcaptionskip
}
\makeatother

\newcommand{\equalcontrib}{\textsuperscript{*}}
\begin{document}
\begin{table}
\centering
\begin{adjustbox}{max width=\textwidth}
\begin{tabular}{@{}c|ccccc@{}}
\toprule
\multirow{2}{*}{\textbf{Model}} & \multicolumn{5}{c}{\textbf{Sliding windows}} \\ \cmidrule(l){2-6}
& \multicolumn{1}{c|}{8} & \multicolumn{1}{c|}{16} & \multicolumn{1}{c|}{32} & \multicolumn{1}{c|}{64} & 128 \\ \midrule
70m & \multicolumn{1}{c|}{0.366**} & \multicolumn{1}{c|}{0.375***} & \multicolumn{1}{c|}{0.427**} & \multicolumn{1}{c|}{\textbf{0.440***}} & 0.370** \\ \midrule
160m & \multicolumn{1}{c|}{0.369***} & \multicolumn{1}{c|}{0.360***} & \multicolumn{1}{c|}{0.426***} & \multicolumn{1}{c|}{\textbf{0.451***}} & 0.378***\\ \midrule
410m & \multicolumn{1}{c|}{0.347***} & \multicolumn{1}{c|}{0.336***} & \multicolumn{1}{c|}{0.430***} & \multicolumn{1}{c|}{\textbf{0.458***}} & 0.378* \\ \midrule
1b & \multicolumn{1}{c|}{0.329***} & \multicolumn{1}{c|}{0.328***} & \multicolumn{1}{c|}{0.431***} & \multicolumn{1}{c|}{\textbf{0.458***}} & 0.367*** \\ \midrule
1.4b & \multicolumn{1}{c|}{0.331**} & \multicolumn{1}{c|}{0.305***} & \multicolumn{1}{c|}{0.423***} & \multicolumn{1}{c|}{\textbf{0.486***}} & 0.388*** \\ \midrule
2.8b & \multicolumn{1}{c|}{0.315***} & \multicolumn{1}{c|}{0.316***} & \multicolumn{1}{c|}{0.435***} & \multicolumn{1}{c|}{\textbf{0.464***}} & 0.365*** \\ \midrule
6.9b & \multicolumn{1}{c|}{0.319**} & \multicolumn{1}{c|}{0.310***} & \multicolumn{1}{c|}{0.420***} & \multicolumn{1}{c|}{\textbf{0.475***}} & 0.370*** \\ \midrule
12b & \multicolumn{1}{c|}{0.317**} & \multicolumn{1}{c|}{0.307***} & \multicolumn{1}{c|}{0.421*} & \multicolumn{1}{c|}{\textbf{0.470***}} & 0.372*** \\ \midrule
LLaMA & \multicolumn{1}{c|}{--} & \multicolumn{1}{c|}{--} & \multicolumn{1}{c|}{--} & \multicolumn{1}{c|}{0.457**} & -- \\ \bottomrule
\addlinespace[1ex]
\multicolumn{3}{l}{\textsuperscript{***}$p<0.01$,
\textsuperscript{**}$p<0.05$,
\textsuperscript{*}$p<0.1$}
\end{tabular}%
\end{adjustbox}
\caption{Table 1: The AVH dataset Spearman's $\rho$ between the \textit{maximum} sliding window PPL and TALD across model size. \textbf{Bold} indicates the highest $\rho$ for a model.}
\end{table}
\end{document}