condition mean min max ZT0-3 20.5768 18.3781 22.7755 ZT4-7 15.1719 15.1719 15.1719 ZT8-11 20.05745 20.05745 20.05745 ZT12-15 0 0 0 ZT16-19 22.8067 22.8067 22.8067 ZT20-23 26.69895 26.69895 26.69895