condition mean min max ZT0-3 13.403509 13.403509 13.403509 ZT4-7 12.563029 12.563029 12.563029 ZT8-11 13.5250205 13.5250205 13.5250205 ZT12-15 11.757288500000001 11.757288500000001 11.757288500000001 ZT16-19 15.315726 15.315726 15.315726 ZT20-23 15.5574995 15.5574995 15.5574995