got a few missed calls from this number as well. i called the number back and its a research study on behalf of usc and ucla. if you give them your number they will remove you from their call list.
Depends on what they asked. It's not necessarily a bad thing to do but why do it? I can see nothing but downside. The survey might have been for real but might have been a scammer. You're under no obligation to answer the survey. Just tell them to put you on their DoNotCall list.