Linked Questions

9
votes
2answers
11k views

Calculate ROC curve for data

So, I have 16 trials in which I am trying to authenticate a person from a biometric trait using Hamming Distance. My threshold is set to 3.5. My data is below and only trial 1 is a True Positive: <...
0
votes
2answers
1k views

How can I plot an ROC curve? [closed]

Given this simple data: How can I plot an ROC curve in Microsoft Excel? Step by step instructions would be very helpful. I know my TPR is ~87% and my FPR is ~13%. How do I know where to set the ...
0
votes
2answers
2k views

what it means to have low ROC AUC?

I have trained two classifiers namely a logistic regression and a decision tree on a data set. When evaluating both models on the testing data set, the decision tree has a ROC AUC = 0.62 but the ...
0
votes
2answers
742 views

ROC accuracy measure error when no positive values

I have an unbalanced dataset that I am working to either up or down sample to balance out. But in the meantime I've run into an interesting error when calculating the AUC in R using ...
2
votes
1answer
33 views

SVM: achieving ROC curve by varying misclassification costs

Assume that we have SVM model for binary classification with objective function as follows: $$ min(\frac{1}{2}\omega\cdot\omega +C^{+}\sum_{i|y_{i}=+1}^{n}\xi_{i}\quad+C^{-}\sum_{i|y_{i}=-1}^{n}\xi_{i}...
2
votes
1answer
849 views

How to draw the ROC curve?

Currently I'm asking me how to draw the ROC curve (Receiver Operating Characteristic curve). On the x-axis there is the false positive rate (1-specificity) and on the y-axis there is the true positive ...
1
vote
1answer
41 views

ROC Curve Horizontal Line

I'm trying to conceptually understand 'why' the horizontal gray line in ROC curve below would be considered random. I know the basics of the ROC in that the farther the curved black line is from the ...
1
vote
1answer
10k views

varying classification threshold to produce ROC curves.

How can I vary classification threshold to produce ROC curves. I am new to R and I wanted to classify in different algorithm. Since the accuracy of ROC plot is high I wanted to change the threshold ...
1
vote
1answer
2k views

How do you use a ROC curve to optimize a random forest classifier? [duplicate]

I am using a random forest for a binary classification problem using sklearn. The sklearn implementation outputs both a predicted class, and a probability for each class. The sklearn implementation ...
1
vote
1answer
526 views

Determining the validity of ROC curves

ROC curves were generated using ROCR package using only actual and predicted labels(from a SVM) as input. Script: ...
0
votes
1answer
155 views

Logistic-regression probability score used for reordering rows for plotting ROC curve: is it the actual, positive, or negative class probability?

I want to draw my own ROC curve, such as explained in the accepted answer to this question: Understanding ROC curve However, it isn't clearly explained what the 'score' used represents. It is used ...
0
votes
1answer
750 views

ROC AUC and PR AUC: Are the AUC values different for each class?

When dealing with a binary classification problem, where the decision function threshold is being varied from 0 to 1 at step 0.1: When calculating the Area Under the Curve (AUC) for a ROC Curve plot (...
2
votes
0answers
75 views

How to calculate the prediction score of a classificator?

I want to compare a given classification algorithm with others via the Area under the (ROC-)curve metric. Unfortunately this algorithm only outputs the values of the respective confusion matrix (TP, ...
0
votes
0answers
56 views

How to interpret ROC curve? [duplicate]

I am currently doing a classification problem for classifying the functional class and non-functional class of peptidase cleavage site. The data on non-functional class (negative class) is highly ...
0
votes
0answers
83 views

How can I plot a ROC from this table? [duplicate]

I'm given a table Class | Probability P .95 N .85 P .78 and so on. I'm asked to construct a ROC. As I understand, a ROC has TP for the ...

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