condition mean min max ZT0-3 15.663284 15.663284 15.663284 ZT4-7 19.464799499999998 19.464799499999998 19.464799499999998 ZT8-11 18.170724 18.170724 18.170724 ZT12-15 16.3092535 16.3092535 16.3092535 ZT16-19 18.5645545 18.5645545 18.5645545 ZT20-23 19.4266055 19.4266055 19.4266055