[Tex/LaTex] Symbol for double cross X

Question

does anyone know what's the LaTeX symbol for the double X, used in a stats book to denote the range?

Answer 1

The symbol can be constructed from the sans serif math font, e.g.:

\documentclass{article}

\newcommand*{\RangeX}{%
  \mathsf{X}\mkern-9mu\mathsf{X}%
}

\begin{document}
  , the \textbf{range} of $X$, denoted $\RangeX$,  
\end{document}

If the symbol is also used in the smaller math styles (\scriptstyle, \scriptscriptstyle), then the width approximation by the \mkern command does not work too well. The following more complicate definition measures the width of the symbol to get a better spacing between the symbols:

\documentclass{article}

\makeatletter
\newcommand*{\RangeX}{%
  {%
    \mathpalette\@RangeOf{X}%
  }%
}
\newcommand*{\@RangeOf}[2]{%
  % #1: math style
  % #2: symbol, which is duplicated
  \sbox0{$\m@th#1\mathsf{#2}$}%
  \mathsf{#2}%
  \kern-\wd0 %
  \mkern2.75mu\relax
  \nonscript\mkern.25mu\relax
  \mathsf{#2}%
}
\makeatother

\begin{document}
  \[ \RangeX \scriptstyle \RangeX \scriptscriptstyle \RangeX \]
\end{document}