[Gsdesign-commits] r328 - pkg/gsDesign/R

[noreply at r-forge.r-project.org]

Author: keaven
Date: 2011-12-30 13:44:18 +0100 (Fri, 30 Dec 2011)
New Revision: 328

Modified:
   pkg/gsDesign/R/nNormal.R
Log:
Replaced nNormal.R

Modified: pkg/gsDesign/R/nNormal.R
===================================================================
--- pkg/gsDesign/R/nNormal.R	2011-12-26 15:03:32 UTC (rev 327)
+++ pkg/gsDesign/R/nNormal.R	2011-12-30 12:44:18 UTC (rev 328)
@@ -1,23 +1,14 @@
 # sample size for fixed design with 2-arms, normal endpoint, 
 # ratio = randomization ratio
-nNormal<-function(delta1=1,sigma=1.7,sigalt=NULL,alpha=.025,beta=.1,ratio=1,delta0=0)
+nNormal<-function(delta1=1,sigma=1.7,sigalt=NULL,alpha=.025,beta=.1,ratio=1,
+                   sided=1, n=NULL,delta0=0)
 {   xi <- ratio/(1+ratio)
+    if (sided==2) alpha <- alpha/2
     if(is.null(sigalt)) sigalt <- sigma
     v <- sigalt^2/xi + sigma^2/(1-xi)
     theta1 <- (delta1-delta0)/sqrt(v)
-    n <- ((qnorm(alpha)+qnorm(beta))/theta1)^2
-    n
+    if (is.null(n))
+       return(((qnorm(alpha)+qnorm(beta))/theta1)^2)
+    else
+       return(pnorm(sqrt(n)*theta1-qnorm(1-alpha)))
 }
-
-# EXAMPLES
-# equal variances
-n.fix <- nNormal(delta1=.5,sigma=1.1,alpha=.025,beta=.2)
-
-# unequal variances
-
-
-# unequal sample sizes 
-
-
-# non-inferiority
-n.fix <- nNormal(delta1=0,delta0=.5,sigma=1.2)