condition mean min max ZT0-3 1.1344283333333334 0.83055 1.721605 ZT4-7 2.4975 2.4975 2.4975 ZT8-11 1.70594 1.70594 1.70594 ZT12-15 1.743085 1.7071 1.77907 ZT16-19 1.593705 1.593705 1.593705 ZT20-23 1.865045 1.865045 1.865045