I search here, Vertical lines in a table, it suggests something like:
\begin{tabular}{cc|ccc|ccc}
I am using:
\toprule
& & \multicolumn{5}{>{\centering\arraybackslash}p{8em}}{\textbf{Bootstrap}} \\
\cmidrule{4-8}
But does not fit in.
My MWE:
\documentclass[12pt,oneside]{book}
\usepackage[showframe]{geometry}
\usepackage{amsmath}
\usepackage{ragged2e}
\usepackage{makecell, multirow, tabularx}
\renewcommand\theadfont{\small\bfseries} % for bold in table using \small
\renewcommand\theadgape{}
\usepackage[svgnames, table]{xcolor}
\usepackage{hhline, boldline}
\usepackage{seqsplit, caption} %for table spacing to second row
\usepackage{booktabs, ragged2e} % Use booktabs rules and get rid of vertical rules, ragged2e to ragged text
\usepackage{siunitx} %for table spacing to second row
\usepackage{threeparttable} %to add footnote below table
\usepackage{tabulary}
\usepackage{graphicx}
\begin{document}
\begin{table}[h!]
\centering
% \begin{center}
%\begin{tabularx}{\textwidth}{@{}M*{6}{N}@{}}
\begin{tabularx}{\textwidth}{>{\RaggedRight\arraybackslash}cXcccccc}
\toprule
& & \multicolumn{5}{>{\centering\arraybackslash}p{8em}}{\textbf{Bootstrap}} \\
\cmidrule{4-8}
&
& \multirow{4.5}{*}{\textbf{Mean}}
& \multirow{4.5}{*}{\textbf{Bias}}
& \multirow{4.5}{*}{\makecell{\textbf{Std.}\\ \textbf{Error}}}
& \multirow{4.5}{*}{\makecell{\textbf{Sig.}\\ \textbf{(2-tailed)}}}
& \multicolumn{2}{>{\centering\arraybackslash}p{8em}}{\textbf{95\% Confidence Interval of the Difference}}
\\
\cmidrule{7-8} %\cmidrule(lr){3-4}
& & & & & & \multicolumn{1}{c}{\textbf{Lower}} & \multicolumn{1}{c}{\textbf{Upper}} \\
\midrule
Pair 1
& \textit{Testing example dataset} (AA) - \textit{Testing puree Example Dataset} (BB)
& 44.76\%
& 0.19\%
& 4.35
& 0.001
& 36.67\%
& 53.33\%\\
\bottomrule
\end{tabularx}
\end{table}
\end{document}



