condition mean min max ZT0-3 4.382954333333333 1.900938 6.338845 ZT4-7 1.96583 1.96583 1.96583 ZT8-11 2.86454 2.86454 2.86454 ZT12-15 5.1558399999999995 4.432345 5.879334999999999 ZT16-19 6.50068 6.50068 6.50068 ZT20-23 6.884835000000001 6.884835000000001 6.884835000000001