condition mean min max ZT0-3 2.8496483333333336 1.20093 4.105855 ZT4-7 0.7256484999999999 0.7256484999999999 0.7256484999999999 ZT8-11 2.764695 2.764695 2.764695 ZT12-15 6.9462425 6.627025 7.26546 ZT16-19 13.9613 13.9613 13.9613 ZT20-23 12.936274999999998 12.936274999999998 12.936274999999998