condition mean min max ZT0-3 7.93362 7.93362 7.93362 ZT4-7 4.442735 4.442735 4.442735 ZT8-11 6.49865 6.49865 6.49865 ZT12-15 9.297915 9.297915 9.297915 ZT16-19 18.1453 18.1453 18.1453 ZT20-23 11.3744 11.3744 11.3744