R: Scatter Plot with Smooth Curve Fitted by Loess

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).

Examples

require(graphics)

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

[Package stats version 2.15.1 Index]