condition mean min max ZT0-3 17.25 17.25 17.25 ZT4-7 1.7 1.7 1.7 ZT8-11 13.7 13.7 13.7 ZT12-15 8.600000000000001 8.600000000000001 8.600000000000001 ZT16-19 18.5 18.5 18.5 ZT20-23 31.4 31.4 31.4