condition mean min max ZT0-3 2.78698 2.78698 2.78698 ZT4-7 2.3403099999999997 2.3403099999999997 2.3403099999999997 ZT8-11 1.95411 1.95411 1.95411 ZT12-15 2.04093 2.04093 2.04093 ZT16-19 2.674455 2.674455 2.674455 ZT20-23 2.884145 2.884145 2.884145