R code for logistic regression on bank note data

tmp<-read.table(file="bankNote.Data", sep=",");

n<-nrow(tmp);

x<-matrix(0,n,ncol(tmp));

for(i in 1:ncol(tmp)) { x[,i]<-tmp[,i];}

idx<-sample(1:n, floor(n/2));

xtr<-x[idx,]; xts<-x[-idx,];

mylogit<-glm(xtr[,5] ~ xtr[,1:4], family=binomial(link="logit"));

b<-mylogit$coefficients;

logits<-matrix(0,nrow(xts),1);

for (i in 1:nrow(xts))

{

logits[i]<-b[1]+sum(xts[i,1:4]*b[2:5]);

}

logits<-exp(logits)/(1+exp(logits));

classDF <- data.frame(response = xts[,5], predicted = round(logits,0))

z<-xtabs(~ predicted + response, data = classDF)

acc<-sum(diag(z))/sum(z);

cat("The accuracy on the test set is", acc,"\n");