condition mean min max ZT0-3 9.1 9.1 9.1 ZT4-7 2.7 2.7 2.7 ZT8-11 20.85 20.85 20.85 ZT12-15 41.0 41.0 41.0 ZT16-19 23.65 23.65 23.65 ZT20-23 10.1 10.1 10.1