condition mean min max ZT0-3 1968.064085 1968.064085 1968.064085 ZT4-7 2058.914062 2058.914062 2058.914062 ZT8-11 1835.814697 1835.814697 1835.814697 ZT12-15 2080.9773370000003 2080.9773370000003 2080.9773370000003 ZT16-19 1563.2537385 1563.2537385 1563.2537385 ZT20-23 2017.080823 2017.080823 2017.080823