
Ultimate access to all questions.
A
The ROC curve plots the true positive rate on the x-axis against the false positive rate on the y-axis and the points on the curve emerge from varying the decision threshold.
B
The AUC shows pictorially how effective the model has been in separating the data points into clusters, with a higher AUC implying a better model fit, but the AUC cannot be used to compare between models.
C
One possible application of the ROC and AUC would be in the context of comparing models to determine whether a loan application should be rejected or accepted.
D
An AUC of 1 would indicate a perfect fit, whereas a value of 0.1 would correspond with an entirely random set of predictions and therefore a model with no predictive ability.