condition mean min max ZT0-3 7.472472499999999 6.92348 8.021465 ZT4-7 6.25743 6.25743 6.25743 ZT8-11 2.59436 2.59436 2.59436 ZT12-15 0 0 0 ZT16-19 1.98821 1.98821 1.98821 ZT20-23 4.402805 4.402805 4.402805