condition mean min max ZT0-3 5.303255 4.96729 5.63922 ZT4-7 4.50416 4.50416 4.50416 ZT8-11 1.8889049999999998 1.8889049999999998 1.8889049999999998 ZT12-15 0 0 0 ZT16-19 2.64121 2.64121 2.64121 ZT20-23 3.849025 3.849025 3.849025