No restrictions: $\displaystyle \binom{16}{6}$
No member is from marketing department: $\displaystyle \binom{8}{6}$
Exactly one member is from marketing department: $\displaystyle \binom{8}{1}\binom{8}{5}$
At least two members are from marketing department: $\displaystyle \binom{16}{6}-\binom{8}{6}-\binom{8}{1}\binom{8}{5}=7532$