condition mean min max ZT0-3 11.487221666666667 8.526715 13.08625 ZT4-7 5.421755 5.421755 5.421755 ZT8-11 5.272935 5.272935 5.272935 ZT12-15 6.63912 6.526415 6.751825 ZT16-19 8.274555 8.274555 8.274555 ZT20-23 13.9362 13.9362 13.9362