condition mean min max ZT0-3 13.116816666666667 10.79375 14.4381 ZT4-7 7.157525 7.157525 7.157525 ZT8-11 3.619115 3.619115 3.619115 ZT12-15 10.2876925 10.270035 10.30535 ZT16-19 16.58535 16.58535 16.58535 ZT20-23 21.43575 21.43575 21.43575