And often, the end user has no idea what information is useful to them until it is presented. In that way dashboards are great: they help the end user figure out what data is important to them.

"2 weeks" may mean the last two calendar weeks, the last and the current calendar week, or the last 14 days. Without even going in to the ambiguity of what a calendar week is (a calender week starts on a Monday, and I will take no opposition), 14 days is less ambiguous (and therefor better) than two weeks. The same goes for the other ones.