condition mean min max ZT0-3 20.536351 20.536351 20.536351 ZT4-7 23.54981 23.54981 23.54981 ZT8-11 26.0239345 26.0239345 26.0239345 ZT12-15 22.5244025 22.5244025 22.5244025 ZT16-19 22.395875 22.395875 22.395875 ZT20-23 22.3215985 22.3215985 22.3215985