[Siegmund]

I daresay you might have a little trouble with the duties of the position, if this is an area you don't know anything about.....

For a start: a) review in your scientific sampling textbook (you DID take sampling at some point, I hope? And DID keep the book?) what the common sampling methods are and the conditions under which each one is appropriate.
b) have an idea of a few of the various things that can cause bias (I won't give you a complete list - non-response bias is one of many) and
c) have an idea of what steps you can take to address bias after you suspect that it exists (there are a few biggies, and you ought to know what phrases to be googling to refresh your memory.)