condition mean min max ZT0-3 17.903416666666665 12.08395 21.23935 ZT4-7 11.089649999999999 11.089649999999999 11.089649999999999 ZT8-11 10.441669999999998 10.441669999999998 10.441669999999998 ZT12-15 13.8293 13.108450000000001 14.55015 ZT16-19 19.721899999999998 19.721899999999998 19.721899999999998 ZT20-23 26.9018 26.9018 26.9018