[Aavso-photometry] stats question

[Michael Koppelman]

What do you think is the best way to combine images like darks and 
flats:

1. mean
2. min/max clipped mean
3. sigma clipped mean
4. median
5. other

Do you think the same "best" method is best for bias, darks and flats 
or is one method better for flats and another method better for darks?

I use min/max clipped mean in most cases.

Cheers,
Michael Koppelman
http://www.lolife.com/astronomy/