Plotting distfreereg Objects
The following code creates the distfreereg object with a
fairly simple setup that is used in most of the examples that
follow.
set.seed(20240214)
n <- 1e2
true_mean <- function(X, theta) theta[1] + theta[2]*X[,1]
theta <- c(2,5)
X <- matrix(runif(n, min = 1, max = 100))
Y <- true_mean(X, theta) + rnorm(n)
dfr <- distfreereg(Y = Y, X = X, test_mean = true_mean,
covariance = list(Sigma = 1),
theta_init = rep(1, length(theta)))Density Plots
The default plot displays the estimated density of the simulated statistics:
The estimated density of the simulated statistic is plotted, as is a vertical line showing the observed statistic. The upper tail is shaded, and the p-value (the area of the shaded region) is shown. A 95% simultaneous confidence band for the estimated density function is plotted, as well.
Modifying the P-Value Label
The plot above is not ideal because the p-value label overlaps the
density curve. The specifications for this label can be modified using
the text_args argument, the elements of which are passed to
graphics::text().
The default placement is vertically centered on the left side of the
vertical line. By using the text_args argument, the text
can be printed on the right side of the line and shifted down a bit.
Note that only the elements to change need to be specified in the list
supplied to text_args.
One special value, text_args = FALSE, prevents the label
from being printed.
Selecting the Statistic to Plot
The stat argument can be used to produce the
corresponding plot for the CvM statistic.
Modifying the Density Calculation and Plotting
The calculation of the density curve can be modified using
density_args, whose elements are passed to
density().
To modify the appearance of the curve once the density curve has been
estimated, pass arguments to plot.default() via the
... argument. The example below shows how to modify the
line type.
Modifying the P-Value Line and Shading
The appearance of the vertical line can be modified using the
abline_args argument, whose elements are passed to
abline(). As with the text label, the line can be omitted
by setting abline_args equal to FALSE.
The shading under the curve is produced by calling
polygon(), and can be modified by passing arguments to that
function via polygon_args. It can also be omitted by
setting polygon_args = FALSE.
As a convenience, the shading color can be changed using the
shade_col argument. This is equivalent to modifying the
col argument of polygon().
Borders
The default behavior is to omit the border of the shaded region. As
seen above, this is notable when the vertical line is omitted. This can
be changed by setting border = NULL, its default value in
polygon(), which (usually) results in a border.
Output
In case the values used to create a plot are useful for further
calculation, each call to plot.distfreereg() invisibly
returns these values in a list with either two or three elements. The
first two elements, x and y, contain the
coordinates of the curve. If confidence bands are plotted, then a third
element named confband is also returned.
## [1] "x" "y" "confband"The \(y\)-values of the curves that
determine the confidence band are saved in the cb_lower and
cb_upper elements, while the \(x\)-values are saved in w.
## [1] "call" "Sigma_hat" "radii" "w" "fnw" "cb_lower"
## [7] "cb_upper"Diagnostic Plots
Below are examples of two diagnostic plots available through
plot.distfreereg().
Residual Plots
A useful diagnostic plot displays the transformed residuals ordered
according to the res_order element of the
distfreereg object.
As with the density plot, all options can be modified if needed by
including additional arguments for plot().
