Modify binary sequential boundary

Description

Modify several different aspects of a binary sequential boundary. Most modifications do not change the stopping boundaries. The exceptions are 'missN', which allows modifications for missing assessments, and 'closeout', which allows for early stopping of the trial for administrative reasons (i.e., reasons that do not depend on the responses in the trial). Other modifications possible: level of the confidence intervals (using tsalpha, conf.level, or alternative), which boundaries are binding (i.e., can change from a boundary with binding futility boundaries to one with non-binding futility boundaries), null hypothesis value (theta0), and whether the confidence intervals should match the non-binding futility p-values on the superiority boundaries (cipMatch).

Usage

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modify(b, missN = NULL, theta0 = NULL, tsalpha = NULL,
    conf.level = NULL, alternative = NULL, cipMatch = TRUE,
    binding = NULL, closeout=NULL,  ...)

Arguments

b

an object of class boundEst

missN

a vector of missed assessments

theta0

null hypothesis probability of success

tsalpha

vector of length 2 with nominal significance level, if not NULL overrides conf.level and alternative

conf.level

confidence level, ignored if tsalpha is not NULL

alternative

character, alternative hypothesis, either 'less', 'greater' or 'two.sided'

cipMatch

logical, for non-binding futility boundaries, should CI match the p-values on the binding boundary

binding

character, which sides are binding: 'both', 'upper', or 'lower'

closeout

total number of trials at early closeout

...

other parameters passed

Value

an object of class boundEst

Examples

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b<-designOBF(50)
bmod<-modify(b,missN=30:36)
par(mfrow=c(2,1))
plot(b)
plot(bmod)