A certain airport security scanner designed to detect explosives in luggage will alert the scanner's operator wheneve...

Marissa on August 31 at 08:57PM

Why E?

Can someone please explain why the answer is E?

1 Reply

Irina on September 5 at 10:21PM

@Marissa-Avnaim,

The argument essentially confuses the percentage of alerts for the pieces of luggage with no explosives with the accuracy of alerts for the luggage that contains explosives. The scanner erroneously alerts the operator for one percent of the pieces of luggage that contain no explosives - that's the false positive rate, we can only infer that in 99% of cases the scanner is accurate when scanning luggage with no explosives, also known as the specificity rate. We have no information to infer what is the true positive rate though, hence the 99% true positive rate conclusion is unwarranted.

Let me know if you have any further questions.