Comment Re:Mired in statistical fallacies (Score 1) 294
"P(S|T) is the probability that the system will identify you as suspicious, given that you are a terrorist. You can call this the system's "accuracy." Let's be generous and say the accuracy is 99.99% = 0.9999."
The definition of accuracy is not accurate:
http://en.wikipedia.org/wiki/Accuracy
Accuracy= (True positives+ True negatives)/Total number of instances
Using your notation: Accuracy = P(S/T)*P(T) + P(~S/~T)*P(~T)
P(S/T) is just the true positive rate (called also Recall)
The definition of accuracy is not accurate:
http://en.wikipedia.org/wiki/Accuracy
Accuracy= (True positives+ True negatives)/Total number of instances
Using your notation: Accuracy = P(S/T)*P(T) + P(~S/~T)*P(~T)
P(S/T) is just the true positive rate (called also Recall)
