condition mean min max ZT0-3 3.4875350000000003 3.4875350000000003 3.4875350000000003 ZT4-7 3.020385 3.020385 3.020385 ZT8-11 2.9589100000000004 2.9589100000000004 2.9589100000000004 ZT12-15 2.3534699999999997 2.3534699999999997 2.3534699999999997 ZT16-19 3.598395 3.598395 3.598395 ZT20-23 2.917875 2.917875 2.917875