# F_3_prepanel.functions

0th

Percentile

##### Useful Prepanel Function for Lattice

These are predefined prepanel functions available in Lattice.

Keywords
dplot
##### Usage
prepanel.lmline(x, y, …)
prepanel.qqmathline(x, y = x, distribution = qnorm,
probs = c(0.25, 0.75), qtype = 7,
groups, subscripts,
…)
prepanel.loess(x, y, span, degree, family, evaluation,
horizontal = FALSE, …)
prepanel.spline(x, y, npoints = 101,
horizontal = FALSE, …,
keep.data = FALSE)
##### Arguments
x, y

x and y values, numeric or factor

distribution

quantile function for theoretical distribution. This is automatically passed in when this is used as a prepanel function in qqmath.

qtype

type of quantile

probs

numeric vector of length two, representing probabilities. If used with aspect="xy", the aspect ratio will be chosen to make the line passing through the corresponding quantile pairs as close to 45 degrees as possible.

span, degree, family, evaluation

Arguments controlling the underlying loess smooth.

horizontal, npoints

See documentation for corresponding panel function.

keep.data

Ignored. Present to capture argument of the same name in smooth.spline.

groups, subscripts

See xyplot. Whenever appropriate, calculations are done separately for each group and then combined.

Other arguments. These are passed on to other functions if appropriate (in particular, smooth.spline), and ignored otherwise.

##### Details

All these prepanel functions compute the limits to be large enough to contain all points as well as the relevant smooth.

In addition, prepanel.lmline computes the dx and dy such that it reflects the slope of the linear regression line; for prepanel.qqmathline, this is the slope of the line passing through the quantile pairs specified by probs. For prepanel.loess and prepanel.spline, dx and dy reflect the piecewise slopes of the nonlinear smooth.

##### Value

usually a list with components xlim, ylim, dx and dy, the first two being used to calculate panel axes limits, the last two for banking computations. The form of these components are described under xyplot. There are also several prepanel functions that serve as the default for high level functions, see prepanel.default.xyplot

Lattice, xyplot, banking, panel.loess, panel.spline.