condition mean min max ZT0-3 5.75 5.75 5.75 ZT4-7 21.2 21.2 21.2 ZT8-11 16.75 16.75 16.75 ZT12-15 16.0 16.0 16.0 ZT16-19 17.45 17.45 17.45 ZT20-23 17.5 17.5 17.5