\begin{Schunk}
\begin{Sinput}
 ### find position 20% "up" vertically, to use for arrow coordinate
 ss = 0.2 * max(myDensity)
 # Insert interval to represent width of one sigma
 arrows( x0=mu, y0= ss, x1=mu+sigma, y1=ss, code=3, angle=90, length=0.1)
 ### Write the value of sigma above that interval
 t2 <-  bquote( sigma== .(round(sigma,2)))
 text( mu+0.5*sigma, 1.15*ss, t2)
\end{Sinput}
\end{Schunk}
