I just got an email from the project manager:

"Hi Team,
Please make sure to review the 7/12 sprint requests for (x project). Please add your estimates even if the requirements are ambiguous. Thank you."

Just hold the 9 key down for a while, that should be about as accurate as they can expect with requests like that.

Think about each item for a bit, triple whatever figure seems a reasonable over-assumption for the scenario you imagined, and then add that without better detail each figure is probably off by a factor of ten?

In my current company we tried agile for a bit. I do very specific research and dev tasks. I literally receive a box which has network port, and I am requested to get all sensible data out of it. Managers tried couple times to get estimates :)