Data visualization example from TikZ & PGF Manual

tikz_datavisualization.tex

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{datavisualization}
\usetikzlibrary{datavisualization.formats.functions}

\begin{document}

\begin{tikzpicture}
\datavisualization [scientific axes=clean]
[
  visualize as smooth line=Gaussian,
  Gaussian={pin in data={text={$e^{-x^2}$},when=x is 0.5}},
]
data [format=function] {
    var x : interval [-7:7] samples 51;
    func y = exp(-\value x*\value x);
}
[
visualize as scatter,
legend={south outside},
scatter={
    style={mark=*,mark size=0.6pt},
    label in legend={text={
            $\sum_{i=1}^{10} x_i$, where $x_i \sim U(-1,1) $}}},
]
data [format=function] {
    var i : interval [0:1] samples 20;
    func y = 0;
    func x = (rand + rand + rand + rand + rand +
    rand + rand + rand + rand + rand);
};

\end{tikzpicture}

\end{document}