condition mean min max ZT0-3 7.041585 4.687395 9.395775 ZT4-7 4.67933 4.67933 4.67933 ZT8-11 11.058945 11.058945 11.058945 ZT12-15 0 0 0 ZT16-19 20.0123 20.0123 20.0123 ZT20-23 4.66167 4.66167 4.66167