condition mean min max ZT0-3 21.85 21.85 21.85 ZT4-7 6.6 6.6 6.6 ZT8-11 10.85 10.85 10.85 ZT12-15 15.5 15.5 15.5 ZT16-19 17.55 17.55 17.55 ZT20-23 5.0 5.0 5.0