condition mean min max ZT0-3 16.43032 16.43032 16.43032 ZT4-7 21.7990715 21.7990715 21.7990715 ZT8-11 19.791438 19.791438 19.791438 ZT12-15 21.8268555 21.8268555 21.8268555 ZT16-19 21.513410999999998 21.513410999999998 21.513410999999998 ZT20-23 23.131716 23.131716 23.131716