Last Column of the \tabularx package does not vertically align

Question

I'm writing a paper and I'm not very familiar with Latex. I have chosen the tabularx environment as it allowed automatic alignment with the text. Although, in the last table that I made, it did a strange thing: the last column was not vertically centered. Can somebody help? I can't find anything working on the internet...thanks a lot!

%helmet
\newcolumntype{s}{>{\hsize=.35\hsize\centering\arraybackslash}X} \newcolumntype{b}{>{\hsize=.07\hsize\centering\arraybackslash}X}
\newcolumntype{c}{>{\hsize=.11\hsize\centering\arraybackslash}X}
\newcolumntype{d}{>{\hsize=.18\hsize\centering\arraybackslash}X}
\begin{table}[htbp] \label{table: valhelmet}
\renewcommand*{\tabularxcolumn}[1]{m{#1}}
\caption{Survey helmet Stanley}
    \centering
    \begin{tabularx}{\textwidth}{| s | b | b | b | b | b || c | d |}
        \hline
        \textbf{Rating:} & \textbf{1} & \textbf{2} & \textbf{3} & \textbf{4} & \textbf{5} & \textbf{Mean} & \textbf{Standard Deviation}
    \\ \hline\hline

    \textbf{Comfort of the helmet}   &  1 & 0 & 2 & 0 & 0 & 2.33 & 1.15

    \\ \hline

    \textbf{Wight of the helmet}   &  0 & 1 & 1 & 1 & 0 & 3.00 & 1.00

    \\ \hline

    \textbf{Comparison between 0having the camera inside (1) and in front (5) of the helmet}   &  2 & 1 & 0 & 0 & 0 & 1.33 & 0.58

    \\ \hline

    \textbf{Communication quality}   &  0 & 1 & 1 & 0 & 1 & 3.33 & 1.53

    \\ \hline

    \textbf{Comparison between HMT-1 (1) and AVATOUR (5): communication}   &  1 & 1 & 0 & 0 & 0 & 1.50 & 0.71

    \\ \hline

     \textbf{Comparison between HMT-1 (1) and AVATOUR (5): overall}   &  0 & 0 & 1 & 1 & 0 & 3.50 & 0.71

    \\ \hline

\end{tabularx}

\end{table}

Answer 1

There is no need for multiple columns derived from the X type. A single X type column and c for the remaining columns should be sufficient. I'd also abbreviatee "Standard Deviation".

In the following MWE, I also included a second example in which I removed all vertical and most horizontal lines, used no bold text and slightly rearranged/shortened the information in the first column:

\documentclass{article}
\usepackage{tabularx}
%%% only used in the second example:
\usepackage{makecell}
\renewcommand{\theadfont}{\normalsize}
\usepackage{booktabs}
\begin{document}
%helmet
\newcolumntype{s}{>{\hsize=.35\hsize\centering\arraybackslash}X} \newcolumntype{B}{>{\hsize=.07\hsize\centering\arraybackslash}X}
\newcolumntype{C}{>{\hsize=.11\hsize\centering\arraybackslash}X}
\newcolumntype{d}{>{\hsize=.19\hsize\centering\arraybackslash}X}
\begin{table}[htbp] 
\renewcommand*{\tabularxcolumn}[1]{m{#1}}
\caption{Survey helmet Stanley}
\label{table: valhelmet} % place this after the caption to prevent wrong cross referencing
    \centering
    \begin{tabularx}{\textwidth}{| >{\centering\arraybackslash}X | c | c | c | c | c || c | c |}
        \hline
        \textbf{Rating:} & \textbf{1} & \textbf{2} & \textbf{3} & \textbf{4} & \textbf{5} & \textbf{Mean} & \textbf{Std.\ Dev.}
    \\ \hline\hline

    \textbf{Comfort of the helmet}   &  1 & 0 & 2 & 0 & 0 & 2.33 & 1.15

    \\ \hline

    \textbf{Wight of the helmet}   &  0 & 1 & 1 & 1 & 0 & 3.00 & 1.00

    \\ \hline

    \textbf{Comparison between 0having the camera inside (1) and in front (5) of the helmet}   &  2 & 1 & 0 & 0 & 0 & 1.33 & 0.58

    \\ \hline

    \textbf{Communication quality}   &  0 & 1 & 1 & 0 & 1 & 3.33 & 1.53

    \\ \hline

    \textbf{Comparison between HMT-1 (1) and AVATOUR (5): communication}   &  1 & 1 & 0 & 0 & 0 & 1.50 & 0.71

    \\ \hline

     \textbf{Comparison between HMT-1 (1) and AVATOUR (5): overall}   &  0 & 0 & 1 & 1 & 0 & 3.50 & 0.71

    \\ \hline

\end{tabularx}

\end{table}
\begin{table}[htbp] 
\caption{Survey helmet Stanley}
\label{table: valhelmet}
    \begin{tabularx}{\textwidth}{X *{7}{c}}
        \toprule
        \thead[l]{Rating} & \thead{1} & \thead{2} & \thead{3} & \thead{4} & \thead{5} & \thead{Mean} & \thead{Std.\ Dev.}   \ 
        \midrule
        Comfort of the helmet                     &  1 & 0 & 2 & 0 & 0 & 2.33 & 1.15 \ \addlinespace
        Weight of the helmet                      &  0 & 1 & 1 & 1 & 0 & 3.00 & 1.00 \ \addlinespace
        Camera position: inside (1) vs. front (5) &  2 & 1 & 0 & 0 & 0 & 1.33 & 0.58 \\addlinespace
        Communication quality                     &  0 & 1 & 1 & 0 & 1 & 3.33 & 1.53 \\addlinespace
        HMT-1 (1) vs. AVATOUR (5)                                                    \
        \quad Communication                       &  1 & 1 & 0 & 0 & 0 & 1.50 & 0.71 \ 
        \quad Overall                             &  0 & 0 & 1 & 1 & 0 & 3.50 & 0.71 \ 
        \bottomrule
\end{tabularx}

\end{table}
\end{document}

Answer 2

Edit: Now is considered talltblr table, available in the tabularray package version 2021M (2021-08-01) up (original answer has used longtblr). It is an alternative to threeparttable environment. It can't cross multiple pages, but it can be put inside table environment.:

\documentclass{article}
\usepackage{tabularray}
\begin{document}
    \begin{table}[htb] 
\begin{talltblr}[
    caption={Survey helmet Stanley},
    label={table: valhelmet},
    note{a} = {\textbf{SD}: \textbf{S}tandard \textbf{D}eviation}
                ]%
    {hlines, vlines,
     hline{1,2,8} =0.8pt,
     vline{7} = 0.8pt,
     colspec = {X[1,l,m] {7}{c}  }, %{7}{c}
     column{1} = {font=\bfseries},
     row{1} = {font=\bfseries},
     }
Rating: & 1 & 2 & 3 & 4 & 5 & Mean & SD\TblrNote{a}     \

Comfort of the helmet
        & 1 & 0 & 2 & 0 & 0 & 2.33 & 1.15   \
Wight of the helmet
        & 0 & 1 & 1 & 1 & 0 & 3.00 & 1.00   \
Comparison between 0 having the camera inside (1) and in front (5) of the helmet
        & 2 & 1 & 0 & 0 & 0 & 1.33 & 0.58   \
Communication quality
        & 0 & 1 & 1 & 0 & 1 & 3.33 & 1.53   \
Comparison between HMT-1 (1) and AVATOUR (5): communication

        & 1 & 1 & 0 & 0 & 0 & 1.50 & 0.71   \
Comparison between HMT-1 (1) and AVATOUR (5): overall
        & 0 & 0 & 1 & 1 & 0 & 3.50 & 0.71   \
\end{talltblr}
    \end{table}
\end{document}