condition mean min max ZT0-3 10.269689 10.269689 10.269689 ZT4-7 12.4877125 12.4877125 12.4877125 ZT8-11 13.5596385 13.5596385 13.5596385 ZT12-15 15.275205999999999 15.275205999999999 15.275205999999999 ZT16-19 23.137673 23.137673 23.137673 ZT20-23 35.708783 35.708783 35.708783