n_shares<-100
n_days<-1
x<-read.csv("http://canisius.edu/~yany/data/ibmDaily.csv")
n<-nrow(x)
LastPrice<-x[n,]$Adj.Close
position<-n_shares*LastPrice
#
p<-x$Adj.Close
ret<-p[2:n]/p[1:(n-1)]-1
mu<-(mean(ret)+1)^n_days-1
std<-sd(ret)
VaR<-position*(mu-2.33*std*sqrt(n_days))
VaR
VaR2<-position*2.33*std
VaR2
(abs(VaR2)-abs(VaR))/abs(VaR)