False positive = (Machine says positive but grand truth is negative) / (Machine says is positive)
In English, a false positive is when the machine declares something as positive but it is actually negative.
This fits a sanity test because ~50% of people that pass through a detector do not get patted down. The truth is closer to 10%. Even then, a true positive probably includes someone with two pennies in their pocket.
You are right this is ML 101, but you are wrong. Someone else has linked the wiki page, and I've posted it elsewhere and I would strongly recommend you read it as your interpretation is very incorrect.
> In English, a false positive is when the machine declares something as positive but it is actually negative.
Yes, and the rate is based on the frequency this happens in your negative set.
>This fits a sanity test because ~50% of people that pass through a detector do not get patted down.
The 50% figure may be wrong, but my definition of what a false positive rate is not.
False positive = (Machine says positive but grand truth is negative) / (Machine says is positive)
In English, a false positive is when the machine declares something as positive but it is actually negative.
This fits a sanity test because ~50% of people that pass through a detector do not get patted down. The truth is closer to 10%. Even then, a true positive probably includes someone with two pennies in their pocket.