condition mean min max ZT0-3 2.5 2.5 2.5 ZT4-7 1.9 1.9 1.9 ZT8-11 20.1 20.1 20.1 ZT12-15 1.8499999999999999 1.8499999999999999 1.8499999999999999 ZT16-19 6.800000000000001 6.800000000000001 6.800000000000001 ZT20-23 2.8 2.8 2.8