condition mean min max ZT0-3 16.726976666666665 7.61503 22.01615 ZT4-7 5.8726400000000005 5.8726400000000005 5.8726400000000005 ZT8-11 14.445649999999999 14.445649999999999 14.445649999999999 ZT12-15 19.133074999999998 18.39975 19.8664 ZT16-19 21.721600000000002 21.721600000000002 21.721600000000002 ZT20-23 31.10445 31.10445 31.10445