#*********sepsis.fix design:

sepsis.fix <- seqDesign(prob.model="proportions",arms=2,size=0.025,power="calculate",
null.hypothesis=c(0.30,0.30),alt.hypothesis=c(0.23,0.30),test.type="less",sample.size=1700)


#*** 4 interim analyses (OBF design):
sepsis.obf <- update(sepsis.fix, nbr.analyses=4)

#*** 4 interim analyses (Futility.8)
Futility.8 <- update(sepsis.obf,P=c(1,0.8))

#**** comparison of Bayesian properties of sepsis.obf and Futility.8:

update(sepsis.obf, display.scale=seqScale("B",priorTheta=-0.09,priorVariation=0.015^2))
STOPPING BOUNDARIES: Bayesian scale
        (Posterior probability of hypotheses based on prior
         distribution having median -0.09
         and variation parameter 0.000225) 
                     Efficacy Futility
    Time 1 (N=  425)        1   0.8521
    Time 2 (N=  850)        1   0.8395
    Time 3 (N= 1275)        1   0.8280
    Time 4 (N= 1700)        1   0.8177

update(Futility.8, display.scale=seqScale("B",priorTheta=-0.09,priorVariation=0.015^2))
STOPPING BOUNDARIES: Bayesian scale
        (Posterior probability of hypotheses based on prior
         distribution having median -0.09
         and variation parameter 0.000225) 
                     Efficacy Futility
    Time 1 (N=  425)        1   0.7954
    Time 2 (N=  850)        1   0.8239
    Time 3 (N= 1275)        1   0.8361
    Time 4 (N= 1700)        1   0.8423