condition mean min max ZT0-3 33.18515 33.18515 33.18515 ZT4-7 21.959249999999997 21.959249999999997 21.959249999999997 ZT8-11 21.708199999999998 21.708199999999998 21.708199999999998 ZT12-15 27.6325 27.6325 27.6325 ZT16-19 39.18535 39.18535 39.18535 ZT20-23 36.72185 36.72185 36.72185