condition mean min max ZT0-3 8.558720000000001 8.558720000000001 8.558720000000001 ZT4-7 7.990935 7.990935 7.990935 ZT8-11 3.5340949999999998 3.5340949999999998 3.5340949999999998 ZT12-15 3.32196 3.32196 3.32196 ZT16-19 3.812 3.812 3.812 ZT20-23 4.293096666666667 4.293096666666667 4.293096666666667