PwrGSD: Ch0C-plot.cpd.PwrGSD – R documentation

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Ch0C-plot.cpd.PwrGSD

Plot Method for cpd.PwrGSD objects

Description

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.

Usage

## S3 method for class 'cpd.PwrGSD'
plot(x, formula, subset, na.action,...)

Arguments

`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

Value

Returns the object, x, invisibly

Note

This processes the cpd.PwrGSD object into a dataframe, stacked on interim looks and then passes the results to the R function coplot

Author(s)

Abovementioned cpd.PwrGSD processing done by Grant Izmirlian <izmirlian@nih.gov>

References

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.

Examples

## See the example in the 'cpd.PwrGSD' documentation

PwrGSD

Power in a Group Sequential Design

v2.3.3

GPL (>= 2)

Authors

Grant Izmirlian <izmirlig@mail.nih.gov>

Initial release