\Header{scatter.smooth}{Scatter Plot with Smooth Curve Fitted by Loess}
\alias{panel.smooth}{scatter.smooth}
\alias{loess.smooth}{scatter.smooth}
\keyword{smooth}{scatter.smooth}
\begin{Usage}
\begin{verbatim}
scatter.smooth(x, y, span=2/3, degree=1,
    family=c("symmetric", "gaussian"),
    xlab=deparse(substitute(x)), ylab=deparse(substitute(y)),
    evaluation=50, ...)
panel.smooth(x, y, span=2/3, degree=1,
    family=c("symmetric", "gaussian"), zero.line=F, evaluation=50, ...)
loess.smooth(x, y, span=2/3, degree=1,
    family=c("symmetric", "gaussian"), zero.line=F, evaluation=50, ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\texttt{x}] x coordinates for scatter plot.
\item[\texttt{y}] y coordinates for scatter plot.
\item[\texttt{span}] smoothness parameter for \texttt{loess}.
\item[\texttt{degree}] degree of local polynomial used.
\item[\texttt{family}] if \texttt{family="gaussian"} fitting is by least-squares,
and if \texttt{family="symmetric"} a re-descending M estimator is used.
\item[\texttt{xlab}] label for x axis.
\item[\texttt{ylab}] label for y axis.
\item[\texttt{zero.line}] logical for plotting a horizontal line at zero -- used
for residual plots.
\item[\texttt{evaluation}] number of points at which to evaluate the smooth curve.
\item[\texttt{...}] graphical parameters.
\end{ldescription}
\end{Arguments}
\begin{Description}
Plot (\texttt{scatter.smooth}) and add a smooth curve computed by
\texttt{loess} to a scatter plot. \texttt{loess.smooth} is an auxiliary
function used by the other two.\end{Description}
\begin{Value}
None.\end{Value}
\begin{Author}
B.D. Ripley\end{Author}
\begin{SeeAlso}
\texttt{\Link{loess}}\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
data(cars)
attach(cars)
scatter.smooth(speed, dist)
detach()
\end{ExampleCode}
\end{Examples}

