condition mean min max ZT0-3 5.124916666666667 4.58826 5.53069 ZT4-7 3.74942 3.74942 3.74942 ZT8-11 14.976299999999998 14.976299999999998 14.976299999999998 ZT12-15 30.928625 30.157600000000002 31.69965 ZT16-19 17.138550000000002 17.138550000000002 17.138550000000002 ZT20-23 19.734650000000002 19.734650000000002 19.734650000000002