condition mean min max ZT0-3 6.6828725 6.06371 7.302035 ZT4-7 5.1955100000000005 5.1955100000000005 5.1955100000000005 ZT8-11 6.400175 6.400175 6.400175 ZT12-15 0 0 0 ZT16-19 6.727895 6.727895 6.727895 ZT20-23 3.7448200000000003 3.7448200000000003 3.7448200000000003