condition mean min max ZT0-3 19.431925 17.53645 21.3274 ZT4-7 8.069865 8.069865 8.069865 ZT8-11 5.884045 5.884045 5.884045 ZT12-15 0 0 0 ZT16-19 11.133334999999999 11.133334999999999 11.133334999999999 ZT20-23 10.18141 10.18141 10.18141