condition mean min max ZT0-3 8.237855 6.898075 9.208559999999999 ZT4-7 6.79413 6.79413 6.79413 ZT8-11 8.37742 8.37742 8.37742 ZT12-15 10.1137075 9.92091 10.306505 ZT16-19 10.953299999999999 10.953299999999999 10.953299999999999 ZT20-23 10.70965 10.70965 10.70965