condition mean min max ZT0-3 7.065819 7.065819 7.065819 ZT4-7 7.0948215 7.0948215 7.0948215 ZT8-11 7.1012125 7.1012125 7.1012125 ZT12-15 7.1538015 7.1538015 7.1538015 ZT16-19 7.3462865 7.3462865 7.3462865 ZT20-23 6.657207 6.657207 6.657207