condition mean min max ZT0-3 12.75 12.75 12.75 ZT4-7 14.2 14.2 14.2 ZT8-11 24.0 24.0 24.0 ZT12-15 17.35 17.35 17.35 ZT16-19 16.15 16.15 16.15 ZT20-23 18.3 18.3 18.3