condition mean min max ZT0-3 20.394208 20.394208 20.394208 ZT4-7 29.47061 29.47061 29.47061 ZT8-11 35.0553865 35.0553865 35.0553865 ZT12-15 19.6365805 19.6365805 19.6365805 ZT16-19 19.366603 19.366603 19.366603 ZT20-23 23.038503 23.038503 23.038503