Function to plot the stopping bounds of an adaptive twostage test
Description
This function plots the stopping bounds of an adaptive twostage test.
Usage
1  plotBounds(a1 = 0, a0 = 1, add = TRUE, xlab = NA, ylab = NA, ...)

Arguments
a1 
alpha1, the efficacy stopping bound and local level of the test after the first stage (default: no stopping for efficacy) 
a0 
alpha0, the futility stopping bound (default: no stopping for futility) 
add 
logical determining whether the bounds should be added to an existing plot (default) or a new plot should be opened 
xlab 
a label for the x axis (default: no label) 
ylab 
a label for the y axis (default: no label) 
... 
arguments to be passed on to the underlying 
Details
This function plots the stopping bounds alpha1 and alpha0 of an adaptive twostage test, either onto an existing plot or into a new plot.
Value
The function plotBounds
is invoked for its plotting effect; it returns no meaningful value.
Note
Note that in this implementation of adaptive twostage tests, early stopping bounds are not part of the conditional error function. Rather, they are specified separately (see also tsT
).
Author(s)
Marc Vandemeulebroecke
See Also
adaptTest
package description, plotCEF
Examples
1 2 3 4 5 6 7  ## Example from Bauer and Koehne (1994): full level after final stage, alpha0 = 0.5
alpha < 0.1
alpha2 < 0.1
alpha0 < 0.5
alpha1 < tsT(typ="b", a=alpha, a0=alpha0, a2=alpha2)
plotCEF(typ="b", a2=alpha2, add=FALSE)
plotBounds(alpha1, alpha0)
