The arithmetic mean of set M is zero

The arithmetic mean of set M is zero. If N = {-2.22; -1.96; -1.68; 1.62; 1.94; 2.16} is the subset of M consisting of all those elements in M which are more than two but less than three standard deviations away from the arithmetic mean of M, what could be equal to the standard deviation of M?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #21858