condition mean min max ZT0-3 15.64235 15.64235 15.64235 ZT4-7 12.3677 12.3677 12.3677 ZT8-11 14.7332 14.7332 14.7332 ZT12-15 12.5303 12.5303 12.5303 ZT16-19 20.044150000000002 20.044150000000002 20.044150000000002 ZT20-23 16.700400000000002 16.700400000000002 16.700400000000002