condition mean min max ZT0-3 27.363445 27.363445 27.363445 ZT4-7 23.118461 23.118461 23.118461 ZT8-11 20.9317085 20.9317085 20.9317085 ZT12-15 21.54522 21.54522 21.54522 ZT16-19 22.240447000000003 22.240447000000003 22.240447000000003 ZT20-23 20.500451499999997 20.500451499999997 20.500451499999997