condition mean min max ZT0-3 2.572061666666667 2.3214300000000003 3.0624450000000003 ZT4-7 6.3409949999999995 6.3409949999999995 6.3409949999999995 ZT8-11 9.669315000000001 9.669315000000001 9.669315000000001 ZT12-15 5.704795 4.849955 6.559635 ZT16-19 4.169565 4.169565 4.169565 ZT20-23 3.8236999999999997 3.8236999999999997 3.8236999999999997