# Normal distribution curve in LaTeX

Amended: 22 February 2016: There were a couple of errors in the code which I have now fixed. The previous code omitted the need for the xcolor package and the some coding items symbols (notably '\' were missing).
I have been searching the internet on how to produce a normal distribution curve in LaTeX with the standard deviations marked. I wasn't able to find exactly what I wanted, but got some good clues here.  This code uses the pgfplots package. The code should work 'as is'.

 \documentclass{article} \usepackage{pgfplots} \usepackage{amssymb, amsmath} \usepackage{tikz} \usepackage{xcolor} \pgfplotsset{compat=1.7} \begin{document} \pgfmathdeclarefunction{gauss}{2}{\pgfmathparse{1/(#2*sqrt(2*pi))*exp(-((x-#1)^2)/(2*#2^2))}% } \begin{tikzpicture} \begin{axis}[no markers, domain=0:10, samples=100, axis lines*=left, xlabel=Standard deviations, ylabel=Frequency,, height=6cm, width=10cm, xtick={-3, -2, -1, 0, 1, 2, 3}, ytick=\empty, enlargelimits=false, clip=false, axis on top, grid = major] \addplot [fill=cyan!20, draw=none, domain=-3:3] {gauss(0,1)} \closedcycle; \addplot [fill=orange!20, draw=none, domain=-3:-2] {gauss(0,1)} \closedcycle; \addplot [fill=orange!20, draw=none, domain=2:3] {gauss(0,1)} \closedcycle; \addplot [fill=blue!20, draw=none, domain=-2:-1] {gauss(0,1)} \closedcycle; \addplot [fill=blue!20, draw=none, domain=1:2] {gauss(0,1)} \closedcycle; \addplot[] coordinates {(-1,0.4) (1,0.4)}; \addplot[] coordinates {(-2,0.3) (2,0.3)}; \addplot[] coordinates {(-3,0.2) (3,0.2)}; \node[coordinate, pin={68.2\%}] at (axis cs: 0, 0.4){}; \node[coordinate, pin={95\%}] at (axis cs: 0, 0.3){}; \node[coordinate, pin={99.7\%}] at (axis cs: 0, 0.2){}; \node[coordinate, pin={34.1\%}] at (axis cs: -0.5, 0){}; \node[coordinate, pin={34.1\%}] at (axis cs: 0.5, 0){}; \node[coordinate, pin={13.6\%}] at (axis cs: 1.5, 0){}; \node[coordinate, pin={13.6\%}] at (axis cs: -1.5, 0){}; \node[coordinate, pin={2.1\%}] at (axis cs: 2.5, 0){}; \node[coordinate, pin={2.1\%}] at (axis cs: -2.5, 0){}; \end{axis} \end{tikzpicture} \end{document}