condition mean min max ZT0-3 3.7584299999999997 3.419605 4.097255 ZT4-7 4.1868549999999995 4.1868549999999995 4.1868549999999995 ZT8-11 7.9174299999999995 7.9174299999999995 7.9174299999999995 ZT12-15 0 0 0 ZT16-19 7.29441 7.29441 7.29441 ZT20-23 6.18136 6.18136 6.18136