Displaying 3 results from an estimated 3 matches for "rocpreds".
2012 Oct 25
2
How to extract auc, specificity and sensitivity
...(n,1,plogis(ystar))
xerr <- x + rnorm(n,0,tau)
model<-glm(z ~ xerr, family=binomial(logit))
int<-coef(model)[1]
slope<-coef(model)[2]
pred<-predict(model)
result<-ifelse(pred>.5,1,0)
accuracy<-length(which(result==z))/length(z)
accuracy
rocpreds<-prediction(result,z)
auc<-performance(rocpreds,"auc")@y.values
sentiv<-performance(rocpreds,"sens")@y.values
sentiv<-slot(fp,"y.values")[[1]]
sentiv<-sentiv[2]
sentiv
specs<-performance(rocpreds,"spec")@y.values...
2012 Oct 20
1
Logistic regression/Cut point? predict ??
...is
the proportion of 0s to 1.
pi0hat<-length(z[which(z==0)]/length(z))
cutmid <- log(pi0hat/pi1hat)
pred<-ifelse(pred>cutmid,1,0) * I am not sure if I need to compare
these two. I think this is an error.
*
accuracy<-length(which(pred==z))/length(z)
accuracy
rocpreds<-prediction(pred,z)
auc<-performance(rocpreds,"auc")@y.values
output<-c(int,slope,cutmid,accuracy,auc)
names(output)<-c("Intercept","Slope","CutPoint","Accuracy","AUC")
return(output)
}
y<-fitglm(.05,1)
y...
2012 Oct 26
0
Problems getting slope and intercept to change when do multiple reps.
...slope*<-coef(model)[2] # when add error you are suppose to get slightly
bias slope. However when I change the beta in the original X, I am not
getting the save average slope as output? strange?
pred<-predict(model,type="response")
cutp<-.5
result<-ifelse(pred>cutp,1,0)
rocpreds<-prediction(result,z)
auc<-performance(rocpreds,"auc")@y.values
accuracy<-length(which(result==z))/length(z)
tn<- sum(z==0 & result==0) # True Negative
fp<- sum(z==0 & result==1) # False Positive
tp<- sum(z==1 & result==1) # True Positive
fn<- s...