condition mean min max ZT0-3 13.818558 13.818558 13.818558 ZT4-7 12.922708499999999 12.922708499999999 12.922708499999999 ZT8-11 12.705521000000001 12.705521000000001 12.705521000000001 ZT12-15 12.268256000000001 12.268256000000001 12.268256000000001 ZT16-19 12.821172 12.821172 12.821172 ZT20-23 13.337989499999999 13.337989499999999 13.337989499999999