condition mean min max ZT0-3 12.085617 12.085617 12.085617 ZT4-7 8.885062000000001 8.885062000000001 8.885062000000001 ZT8-11 10.244629 10.244629 10.244629 ZT12-15 9.229078000000001 9.229078000000001 9.229078000000001 ZT16-19 10.852958000000001 10.852958000000001 10.852958000000001 ZT20-23 10.605865999999999 10.605865999999999 10.605865999999999