condition mean min max ZT0-3 1.5808325 1.28662 1.87692 ZT4-7 1.048491 1.048491 1.048491 ZT8-11 0.9172055 0.9172055 0.9172055 ZT12-15 1.3357875 1.294635 1.3769399999999998 ZT16-19 1.4350649999999998 1.4350649999999998 1.4350649999999998 ZT20-23 1.891975 1.891975 1.891975