This is a helpful table for converting sigma levels to percents and fractions (although those you listed are pretty good rules of thumb): https://en.m.wikipedi

This is a helpful table for converting sigma levels to percents and fractions (although those you listed are pretty good rules of thumb): https://en.m.wikipedia.org/wiki/68–95–99.7_rule#Table_of_numerical_values https://en.m.wikipedia.org/wiki/68–95–99.7_rule#Table_of_num...