condition mean min max ZT0-3 6.595565000000001 6.120705 7.070425 ZT4-7 5.662765 5.662765 5.662765 ZT8-11 6.12717 6.12717 6.12717 ZT12-15 0 0 0 ZT16-19 7.54514 7.54514 7.54514 ZT20-23 8.880030000000001 8.880030000000001 8.880030000000001