condition mean min max ZT0-3 30.900000000000002 30.900000000000002 30.900000000000002 ZT4-7 30.8 30.8 30.8 ZT8-11 17.5 17.5 17.5 ZT12-15 5.300000000000001 5.300000000000001 5.300000000000001 ZT16-19 17.8 17.8 17.8 ZT20-23 7.75 7.75 7.75