condition mean min max ZT0-3 3.0534825000000003 2.874215 3.2327500000000002 ZT4-7 3.391375 3.391375 3.391375 ZT8-11 7.517445 7.517445 7.517445 ZT12-15 0 0 0 ZT16-19 6.049135 6.049135 6.049135 ZT20-23 4.94317 4.94317 4.94317