condition mean min max ZT0-3 2.542825 2.22987 2.85578 ZT4-7 15.9177 15.9177 15.9177 ZT8-11 20.5205 20.5205 20.5205 ZT12-15 0 0 0 ZT16-19 6.160785000000001 6.160785000000001 6.160785000000001 ZT20-23 6.355285 6.355285 6.355285