Define false positive and false negative?

Means there was a test done and now it is understood that the test was wrong. i.e. a pregnant woman uses a pregnancy test and it shows up negative then sees her doctor and found out the test was a...

Yes. Both are quite possible.

With an MRI or any other assessment, a false negative is when the test says nothing of concern is present when something actually is. In other words, when a test fails to detect something that is...

All the answers are false.

False positive is a test result which indicates that a person has a disease or condition when, in reality, that condition/disease is not present.