condition mean min max ZT0-3 5.191866666666667 4.581835 6.147425 ZT4-7 8.873335 8.873335 8.873335 ZT8-11 17.60245 17.60245 17.60245 ZT12-15 10.4760225 8.910245 12.0418 ZT16-19 7.79183 7.79183 7.79183 ZT20-23 7.627269999999999 7.627269999999999 7.627269999999999