condition mean min max ZT0-3 11.805043 11.805043 11.805043 ZT4-7 17.9159225 17.9159225 17.9159225 ZT8-11 25.371848999999997 25.371848999999997 25.371848999999997 ZT12-15 20.4655375 20.4655375 20.4655375 ZT16-19 21.715511 21.715511 21.715511 ZT20-23 16.6090835 16.6090835 16.6090835