plotDens1 {MLEcens}

Create a univariate density plot of the MLE

Description

This function creates a univariate density plot of the MLE. To be precise, it can plot the density (d/dx) P(X<=x, a<Y<=b) as a function of x, and (d/dy) P(a<X<=b, Y<=y) as a function of y, under the assumption that the mass is distributed uniformly over the maximal intersections.

Usage

plotDens1(mle, margin, int=NULL, col=1, lty=1, add=FALSE,
          xlim=NULL, ylim=NULL, xlab="", ylab="", main="", sub="")

Arguments

mle

List with elements 'p' and 'rects', as outputted by computeMLE.

margin

Indicates which margin should be plotted: 1 = x-margin, 2 = y-margin. So if margin=1, the MLE for (d/dx) P(X<=x, a<Y<=b) is plotted, and if margin=2, then the MLE for (d/dy) P(a<X<=b, Y<=y) is plotted.

int

This indicates the range of interest of the variable that was not chosen in margin. If int is specified, it should be of the form c(a,b), with a<b. If margin=1, the MLE for (d/dx) P(X<=x, a<Y<=b) is plotted as a function of x. If margin=2, the MLE for (d/dy) P(a<X<=b, Y<=y) is plotted as a function of y. This parameter defaults to (-infinity,infinity), yielding plots of the marginal density of X and Y.

col

Line color. The default value is 1="black".

lty

Line type. The default value is 1="solid".

add

Logical, indicating if the lines should be added to an existing plot. The default value is FALSE.

xlim

Range for the horizontal axis, defaulting to the range of x-coordinates (if margin=1) or y-coordinates (if margin=2) of the relevant corners of maximal interesctions.

ylim

Range for the vertical axis, defaulting to the range of values of the estimate.

xlab, ylab

Labels of the x- and y-axis. The default values are empty.

main

Title of the plot.

sub

Sub title of the plot.

Details

In many cases we assign specific values to represent +/- infinity and (see, e.g., actg181). Note that these values determine the size of maximal intersections that extend to +/- infinity, and hence they also determine the value of the density at such maximal intersections. The value of the density at such maximal intersections is therefore meaningless.

Value

No value is returned.

Author(s)

Marloes Maathuis: [e-mail]

See Also

computeMLE

Examples

# Load example data:
data(ex)

# Compute the MLE:
mle <- computeMLE(ex)

# Bivariate density plot of the MLE:
# (Numbers represent the mass p in the maximal intersections)
par(mfrow=c(2,2))
plotDens2(mle, xlim=range(ex[,1:2]), ylim=range(ex[,3:4]), 
 col="lightgray", main="Bivariate density plot of the MLE", 
 key=FALSE, numbers=TRUE)
plotRects(ex, add=TRUE)

### Univariate density plots of the MLE:

# Plot of the marginal density of Y
plotDens1(mle, margin=2, xlim=range(ex[,3:4]), 
 main="Marginal density plot, 
 y-margin", xlab="y", ylab=expression(f[Y](y))) 

# Plot of the marginal density of X 
plotDens1(mle, margin=1, xlim=range(ex[,1:2]), 
 main="Marginal density plot, 
 x-margin", xlab="x", ylab=expression(f[X](x)))