condition mean min max ZT0-3 2.528471666666667 1.580075 3.8184750000000003 ZT4-7 1.0212249999999998 1.0212249999999998 1.0212249999999998 ZT8-11 1.3260399999999999 1.3260399999999999 1.3260399999999999 ZT12-15 4.7730175 3.117095 6.428940000000001 ZT16-19 6.434175 6.434175 6.434175 ZT20-23 7.74257 7.74257 7.74257