condition mean min max ZT0-3 16.884225 15.744499999999999 18.02395 ZT4-7 14.90895 14.90895 14.90895 ZT8-11 21.098950000000002 21.098950000000002 21.098950000000002 ZT12-15 0 0 0 ZT16-19 26.1463 26.1463 26.1463 ZT20-23 25.6292 25.6292 25.6292