condition mean min max ZT0-3 6.5865975 6.28275 6.890445 ZT4-7 5.9170549999999995 5.9170549999999995 5.9170549999999995 ZT8-11 3.1855450000000003 3.1855450000000003 3.1855450000000003 ZT12-15 0 0 0 ZT16-19 5.23926 5.23926 5.23926 ZT20-23 7.425245 7.425245 7.425245