condition mean min max ZT0-3 19.0 19.0 19.0 ZT4-7 2.5 2.5 2.5 ZT8-11 5.7 5.7 5.7 ZT12-15 11.0 11.0 11.0 ZT16-19 5.75 5.75 5.75 ZT20-23 2.75 2.75 2.75