condition mean min max ZT0-3 1.8503183333333335 1.7275550000000002 2.085735 ZT4-7 2.19727 2.19727 2.19727 ZT8-11 1.73139 1.73139 1.73139 ZT12-15 2.8694975 2.833075 2.90592 ZT16-19 1.79337 1.79337 1.79337 ZT20-23 2.236645 2.236645 2.236645