condition mean min max ZT0-3 17.740296 17.740296 17.740296 ZT4-7 20.400298 20.400298 20.400298 ZT8-11 21.1047205 21.1047205 21.1047205 ZT12-15 20.9059115 20.9059115 20.9059115 ZT16-19 29.370371499999997 29.370371499999997 29.370371499999997 ZT20-23 33.233263 33.233263 33.233263