condition mean min max ZT0-3 12.100000000000001 12.100000000000001 12.100000000000001 ZT4-7 9.1 9.1 9.1 ZT8-11 16.0 16.0 16.0 ZT12-15 23.150000000000002 23.150000000000002 23.150000000000002 ZT16-19 22.3 22.3 22.3 ZT20-23 12.299999999999999 12.299999999999999 12.299999999999999