condition mean min max ZT0-3 26.281775 26.04905 26.514499999999998 ZT4-7 23.10175 23.10175 23.10175 ZT8-11 28.9454 28.9454 28.9454 ZT12-15 0 0 0 ZT16-19 38.8217 38.8217 38.8217 ZT20-23 31.0345 31.0345 31.0345