condition mean min max ZT0-3 17.9682 17.481099999999998 18.4553 ZT4-7 19.88355 19.88355 19.88355 ZT8-11 15.71425 15.71425 15.71425 ZT12-15 0 0 0 ZT16-19 17.68255 17.68255 17.68255 ZT20-23 22.1255 22.1255 22.1255