condition mean min max ZT0-3 1.4912533333333333 1.22962 1.896715 ZT4-7 1.22024 1.22024 1.22024 ZT8-11 2.05936 2.05936 2.05936 ZT12-15 6.3225 5.781635 6.863365 ZT16-19 4.061915 4.061915 4.061915 ZT20-23 3.057015 3.057015 3.057015