condition mean min max ZT0-3 19.796125 19.305 20.28725 ZT4-7 8.865585 8.865585 8.865585 ZT8-11 7.62805 7.62805 7.62805 ZT12-15 0 0 0 ZT16-19 19.13335 19.13335 19.13335 ZT20-23 25.53585 25.53585 25.53585