condition mean min max ZT0-3 15.2 15.2 15.2 ZT4-7 15.5 15.5 15.5 ZT8-11 8.0 8.0 8.0 ZT12-15 13.85 13.85 13.85 ZT16-19 17.1 17.1 17.1 ZT20-23 13.8 13.8 13.8