GroupSeq (version 1.0)

useSpendingFunction: computes bounds

Description

This function runs in the console mode - it computes bounds using a user chosen spending function

Usage

useSpendingFunction(t, n, t2)

Arguments

t

is the vector of information times.

n

is the number of interim analyses.

t2

is the 'second' time scale, used for the covariance of sequential statistics, usually number of events or subjects.

Value

• alpha
  is the total type I error.
• lowerBounds
  the vector of lower standardized boundaries
• upperBounds
  the vector of upper standardized boundaries
• probExit
  is a vector of exit probabilities
• probDifference
  probDifference(i) = probExit(i)-probExit(i-1) where probExit is a vector of exit probabilities.
• symmetricBounds
  denotes whether symmetric bounds are used(symmetricBounds==TRUE) or not(symmetricBounds==FALSE)
• whatSpendingFunctionIsUsed
  denotes the spending function which is used, (e.g. Pocock Type=> whatSpendingFunctionIsUsed<-2, etc...)
• OneOrTwoSidedBounds
  One-(OneOrTwoSidedBounds==1) or Two-sided bounds(OneOrTwoSidedBounds==2)

Details

This function works in an interactive mode in the R console. It asks user for some input before calculating and printing the output.

See Also

groupseq, computeBounds calculateEqualBounds, computeAlphaLevel

Examples

## simple example - always interactive dialogue will open to get necessary input from user  - so try by yourself
# useSpendingFunction( c(0.5,1.0), 2, c(0.2,0.4) )