condition mean min max ZT0-3 24.2 24.2 24.2 ZT4-7 18.9 18.9 18.9 ZT8-11 12.7 12.7 12.7 ZT12-15 19.35 19.35 19.35 ZT16-19 6.300000000000001 6.300000000000001 6.300000000000001 ZT20-23 8.9 8.9 8.9