# scatter.smooth

##### Scatter Plot with Smooth Curve Fitted by Loess

Plot and add a smooth curve computed by `loess`

to a scatter plot.

- Keywords
- smooth

##### Usage

```
scatter.smooth(x, y = NULL, span = 2/3, degree = 1,
family = c("symmetric", "gaussian"),
xlab = NULL, ylab = NULL,
ylim = range(y, pred$y, na.rm = TRUE),
evaluation = 50, …, lpars = list())
```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. Can be abbreviated.- 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.

- …
For

`scatter.smooth()`

, graphical parameters, passed to`plot()`

only. For`loess.smooth`

, control parameters passed to`loess.control`

.- lpars

##### 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`

; `smoothScatter`

for scatter plots
with smoothed *density* color representation.

##### Examples

`library(stats)`

```
# NOT RUN {
require(graphics)
with(cars, scatter.smooth(speed, dist))
## or with dotted thick smoothed line results :
with(cars, scatter.smooth(speed, dist, lpars =
list(col = "red", lwd = 3, lty = 3)))
# }
```

*Documentation reproduced from package stats, version 3.5.0, License: Part of R 3.5.0*