condition mean min max ZT0-3 4.0 4.0 4.0 ZT4-7 4.6 4.6 4.6 ZT8-11 6.5 6.5 6.5 ZT12-15 16.299999999999997 16.299999999999997 16.299999999999997 ZT16-19 10.0 10.0 10.0 ZT20-23 6.300000000000001 6.300000000000001 6.300000000000001