condition mean min max ZT0-3 6.0082699999999996 6.0082699999999996 6.0082699999999996 ZT4-7 6.01345 6.01345 6.01345 ZT8-11 6.9435199999999995 6.9435199999999995 6.9435199999999995 ZT12-15 6.137615 6.137615 6.137615 ZT16-19 6.1063849999999995 6.1063849999999995 6.1063849999999995 ZT20-23 4.5200499999999995 4.5200499999999995 4.5200499999999995