plot.cpd.PwrGSD {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 <[e-mail]>

References

Chambers, J. M. (1992) Data for models. Chapter 3 of Statistical Models in S eds J. M. Chambers and T. J. Hastie, Wadsworth and Brooks/Cole.

Cleveland, W. S. (1993) Visualizing Data. New Jersey: Summit Press.

See Also

cpd.PwrGSD Power and Elements

Examples

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