condition mean min max ZT0-3 8.605562 8.605562 8.605562 ZT4-7 8.8379965 8.8379965 8.8379965 ZT8-11 8.521871 8.521871 8.521871 ZT12-15 8.1257875 8.1257875 8.1257875 ZT16-19 8.100849 8.100849 8.100849 ZT20-23 8.215088999999999 8.215088999999999 8.215088999999999