condition mean min max ZT0-3 12.584818333333333 8.827505 14.65395 ZT4-7 12.2619 12.2619 12.2619 ZT8-11 22.42805 22.42805 22.42805 ZT12-15 23.1802 21.49785 24.86255 ZT16-19 19.161900000000003 19.161900000000003 19.161900000000003 ZT20-23 18.89705 18.89705 18.89705