computeAlphaLevel {GroupSeq} | R Documentation |
Computes alpha level and other probabilities for the number of tests of hypotheses. Method is a modification of Armitage, McPherson and Rowe. Consistent with Lan & DeMets 83, does not assume equally spaced information times.
computeAlphaLevel(n, t, t2, lowerBounds, upperBounds, drift, nMax)
n |
the number of analyses |
t |
the vector of analysis time point on (0,1). |
t2 |
is the second or information time scale, for covariances |
lowerBounds |
the vector of upper bounds (standardized) |
upperBounds |
the vector of lower bounds (standardized) |
drift |
the noncentrality; at t=1, process has mean drift. |
nMax |
Number of interim analyses is limited to nMax=25 . |
probStopping(i) |
is the prob of reaching ith analysis and stopping. |
probExceedingUpper(i) |
is the prob of reaching ith and exceeding upper. |
probExceedingLower(i) |
is the prob of reaching ith and exceeding lower. |
expectedStoppingTime |
is expected stopping time (not implemented). |
probTotal |
is the total type I error used. |
This function is meant to be called in context of using groupseq
Roman Pahl
Armitage, McPherson & Rowe 1969 JRSSA
Lan & DeMets 1983 Biometrika http://www.biostat.wisc.edu/landemets/
groupseq
, stdDeviations
pnorm
, jointDensity
## fictious example computeAlphaLevel(3, c(0.33,0.66,1),c(0.33,0.66,1), c(-1,0,1), c(2,3,4),0.2, 25) ## with following result: # $probAndStop # [1] 0.1621561 1.0000000 1.0000000 # # $probAndExceedingUpper # [1] 2.970758e-02 7.447682e-04 9.675729e-06 # # $probAndExceedingLower # [1] 0.1324485 0.3115237 0.3327052 # # $expectedStoppingTime # [1] 0 # # $totalTypeOneError # [1] 0.8071395 #