condition mean min max ZT0-3 1.6486500000000002 1.6486500000000002 1.6486500000000002 ZT4-7 2.09065 2.09065 2.09065 ZT8-11 0.9168179999999999 0.9168179999999999 0.9168179999999999 ZT12-15 0.9606465 0.9606465 0.9606465 ZT16-19 1.121296 1.121296 1.121296 ZT20-23 1.9815966666666667 1.9815966666666667 1.9815966666666667