condition mean min max ZT0-3 16.115421666666666 6.602715 21.91085 ZT4-7 6.304665 6.304665 6.304665 ZT8-11 8.504439999999999 8.504439999999999 8.504439999999999 ZT12-15 13.64199 10.57288 16.711100000000002 ZT16-19 22.269399999999997 22.269399999999997 22.269399999999997 ZT20-23 22.9601 22.9601 22.9601