condition mean min max ZT0-3 12.820343333333334 10.15938 14.5299 ZT4-7 6.080795 6.080795 6.080795 ZT8-11 7.594984999999999 7.594984999999999 7.594984999999999 ZT12-15 12.0245575 10.034165000000002 14.014949999999999 ZT16-19 12.0064 12.0064 12.0064 ZT20-23 15.753 15.753 15.753