condition mean min max ZT0-3 83.23355 79.2909 87.1762 ZT4-7 32.02655 32.02655 32.02655 ZT8-11 19.762999999999998 19.762999999999998 19.762999999999998 ZT12-15 0 0 0 ZT16-19 38.9401 38.9401 38.9401 ZT20-23 42.5656 42.5656 42.5656