x<-read.csv("http://datayyy.com/data_csv/ibmDaily.csv")
n<-nrow(x)
p<-x$Adj.Close

ret<-p[2:n]/p[1:(n-1)]-1
mean(ret)/(2.33*sd(ret))  
# 0.01196252     
mean(ret)/(mean(ret)+2.33*sd(ret))           
# [1] 0.01182111