condition mean min max ZT0-3 2.402769 1.423098 3.38244 ZT4-7 5.62135 5.62135 5.62135 ZT8-11 8.05263 8.05263 8.05263 ZT12-15 0 0 0 ZT16-19 8.319755 8.319755 8.319755 ZT20-23 6.7009799999999995 6.7009799999999995 6.7009799999999995