condition mean min max ZT0-3 11.6 11.6 11.6 ZT4-7 5.8 5.8 5.8 ZT8-11 5.35 5.35 5.35 ZT12-15 4.300000000000001 4.300000000000001 4.300000000000001 ZT16-19 16.1 16.1 16.1 ZT20-23 7.75 7.75 7.75