Following in the footsteps of P. Erd\H{o}s and A. R\'enyi we compute the
Hausdorff dimension of sets of numbers whose digits with respect to their
Q-Cantor series expansions satisfy various statistical properties. In
particular, we consider difference sets associated with various notions of
normality and sets of numbers with a prescribed range of digits.Comment: 13 pages, 1 figur