scatter.smooth {stats}

R Documentation

Scatter Plot with Smooth Curve Fitted by Loess

Description

Plot and add a smooth curve computed by loess to a scatter plot.

Usage

scatter.smooth(x, y = NULL, span = 2/3, degree = 1,
    family = c("symmetric", "gaussian"),
    xlab = NULL, ylab = NULL,
    ylim = range(y, prediction$y, na.rm = TRUE),
    evaluation = 50, ...)

loess.smooth(x, y, span = 2/3, degree = 1,
    family = c("symmetric", "gaussian"), evaluation = 50, ...)

Arguments

x, y	the x and y arguments provide the x and y coordinates for the plot. Any reasonable way of defining the coordinates is acceptable. See the function xy.coords for details.
span	smoothness parameter for loess.
degree	degree of local polynomial used.
family	if "gaussian" fitting is by least-squares, and if family="symmetric" a re-descending M estimator is used.
xlab	label for x axis.
ylab	label for y axis.
ylim	the y limits of the plot.
evaluation	number of points at which to evaluate the smooth curve.
...	graphical parameters.

Details

loess.smooth is an auxiliary function which evaluates the loess smooth at evaluation equally spaced points covering the range of x.

Value

For scatter.smooth, none.

For loess.smooth, a list with two components, x (the grid of evaluation points) and y (the smoothed values at the grid points).

See Also

loess

Examples

require(graphics)

with(cars, scatter.smooth(speed, dist))

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