condition mean min max ZT0-3 9.508293333333333 5.0042 12.93675 ZT4-7 4.69323 4.69323 4.69323 ZT8-11 4.90504 4.90504 4.90504 ZT12-15 9.346319999999999 7.54509 11.147549999999999 ZT16-19 12.024000000000001 12.024000000000001 12.024000000000001 ZT20-23 14.81275 14.81275 14.81275