condition mean min max ZT0-3 1.304475 1.304475 1.304475 ZT4-7 1.963415 1.963415 1.963415 ZT8-11 1.7016300000000002 1.7016300000000002 1.7016300000000002 ZT12-15 0.792752 0.792752 0.792752 ZT16-19 1.0011505 1.0011505 1.0011505 ZT20-23 0.8873264999999999 0.8873264999999999 0.8873264999999999