condition mean min max ZT0-3 39.367016666666665 17.83265 52.836349999999996 ZT4-7 17.2649 17.2649 17.2649 ZT8-11 19.898699999999998 19.898699999999998 19.898699999999998 ZT12-15 28.997625 24.11275 33.8825 ZT16-19 40.59705 40.59705 40.59705 ZT20-23 53.6251 53.6251 53.6251