condition mean min max ZT0-3 10.0 10.0 10.0 ZT4-7 4.0 4.0 4.0 ZT8-11 25.5 25.5 25.5 ZT12-15 50.3 50.3 50.3 ZT16-19 6.800000000000001 6.800000000000001 6.800000000000001 ZT20-23 20.1 20.1 20.1