plot.cpd.PwrGSD {PwrGSD} | R Documentation |
Creates a trellis plot of type II error probability and power at each interim analysis, stacked, versus an effect size variable, conditioned upon levels of up to two factors.
## S3 method for class 'cpd.PwrGSD': plot(x, formula, subset, na.action,...)
x |
an object of class cpd.PwrGSD |
formula |
a one sided formula of the form ~ effect | f1
or ~ effect | f1 * f2 where effect , f1 , and
f2 are variables in the indexing dataframe descr , or
the special variable stat which may be used when there are
multiple test statistics per component of Elements . See
the example in the documentation for cpd.PwrGSD |
subset |
the plot can be applied to a subset of rows of
descr via a logical expression on its variables in
combination with the special variable, stat when applicable. |
na.action |
a na.action method for handling NA
values |
... |
other parameters to pass to the R function coplot
usually not neccesary |
Returns the object, x
, invisibly
This processes the cpd.PwrGSD
object into a dataframe,
stacked on interim looks and then passes the results to the R
function coplot
Abovementioned cpd.PwrGSD
processing done by Grant
Izmirlian <izmirlian@nih.gov>
Chambers, J. M. (1992) Data for models. Chapter 3 of Statistical Models in S eds J. M. Chambers and T. J. Hastie, Wadsworth & Brooks/Cole.
Cleveland, W. S. (1993) Visualizing Data. New Jersey: Summit Press.
cpd.PwrGSD
Power
and Elements
## See the example in the 'cpd.PwrGSD' documentation