This is actually a pretty standard question by psychiatrists. It's because the DSM-V criteria for Major Depressive Disorder is "Depressed most of the day, nearly every day..." - and it's one of several other features you have to match within a 2 week period to match it.
It's a fancy way of saying "The unusual depressive episode (which can be normal) has lasted at least two weeks (not as normal)". How that exact number was determined I'm not sure (though it was the APA), but that's the standard everyone follows.
EDIT: I believe a variation of this question is standard as part of the PHQ-9 which is a screening/benchmark quick self-assessment for depression.
It's a fancy way of saying "The unusual depressive episode (which can be normal) has lasted at least two weeks (not as normal)". How that exact number was determined I'm not sure (though it was the APA), but that's the standard everyone follows.
EDIT: I believe a variation of this question is standard as part of the PHQ-9 which is a screening/benchmark quick self-assessment for depression.