We derive a two-parameter family of generalized entropies, Spq, and means mpq. To this end, assume that we want to calculate an entropy and a mean for n non-negative real numbers {x1,...,xn}. For comparison, we consider {m1,...,mk} where mi = m for all i = 1,...,k and where m and k are chosen such that the l and l norms of {x1,...,xn} and {m1,...,mk} coincide. We formally allow k to be real. Th...