condition mean min max ZT0-3 18.75 18.75 18.75 ZT4-7 24.1 24.1 24.1 ZT8-11 16.55 16.55 16.55 ZT12-15 7.4 7.4 7.4 ZT16-19 7.55 7.55 7.55 ZT20-23 19.8 19.8 19.8