condition mean min max ZT0-3 1.090714 1.090714 1.090714 ZT4-7 1.5024725 1.5024725 1.5024725 ZT8-11 1.30599 1.30599 1.30599 ZT12-15 1.89795 1.89795 1.89795 ZT16-19 3.4901649999999997 3.4901649999999997 3.4901649999999997 ZT20-23 1.37222 1.37222 1.37222