condition mean min max ZT0-3 4.5356016666666665 3.369675 6.050425000000001 ZT4-7 4.16576 4.16576 4.16576 ZT8-11 5.11091 5.11091 5.11091 ZT12-15 6.076535 4.9611350000000005 7.191934999999999 ZT16-19 6.545985 6.545985 6.545985 ZT20-23 6.619995 6.619995 6.619995