condition mean min max ZT0-3 6.220505 3.68014 8.76087 ZT4-7 4.49469 4.49469 4.49469 ZT8-11 3.78848 3.78848 3.78848 ZT12-15 5.876471666666667 4.999723333333334 6.75322 ZT16-19 6.972099999999999 6.08552 7.85868 ZT20-23 0 0 0