condition mean min max ZT0-3 17.4 17.4 17.4 ZT4-7 35.3 35.3 35.3 ZT8-11 26.75 26.75 26.75 ZT12-15 16.15 16.15 16.15 ZT16-19 15.850000000000001 15.850000000000001 15.850000000000001 ZT20-23 13.8 13.8 13.8