condition mean min max ZT0-3 14.987975735 11.87879433 18.09715714 ZT4-7 15.4835392775 12.82350802 18.143570535000002 ZT8-11 21.73459688 21.369490675 22.099703085 ZT12-15 25.822462395 25.587477104999998 26.057447685 ZT16-19 30.75480759 29.01679252 32.49282266 ZT20-23 30.4515690125 29.87287852 31.030259504999997