95% certainty is also, for a normal distribution, two standard deviations. Two sigma events happen very regularly. https://en.m.wikipedia.org/wiki/68%E2%80%93

95% certainty is also, for a normal distribution, two standard deviations. Two sigma events happen very regularly. https://en.m.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule https://en.m.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_r...