condition mean min max ZT0-3 8.71743 8.71743 8.71743 ZT4-7 4.89287 4.89287 4.89287 ZT8-11 7.05835 7.05835 7.05835 ZT12-15 9.37002 9.37002 9.37002 ZT16-19 12.31405 12.31405 12.31405 ZT20-23 10.20015 10.20015 10.20015