condition mean min max ZT0-3 15.9413 15.9413 15.9413 ZT4-7 14.13375 14.13375 14.13375 ZT8-11 18.63695 18.63695 18.63695 ZT12-15 19.0867 19.0867 19.0867 ZT16-19 17.9643 17.9643 17.9643 ZT20-23 15.68345 15.68345 15.68345