Think of it this way... You're logging incoming web requests and then gathering statistics in 5 minute intervals. During one interval, you get no requests. Y

Think of it this way... You're logging incoming web requests and then gathering statistics in 5 minute intervals. During one interval, you get no requests. You check to see...did "all" of the requests get processed without errors? The answer is Yes, because to say No would imply there were errors. Did "any" of the requests cause an error? The answer is No, because to say Yes would imply at least one error.