condition mean min max ZT0-3 15.996883 15.996883 15.996883 ZT4-7 16.467376 16.467376 16.467376 ZT8-11 14.691969 14.691969 14.691969 ZT12-15 15.4498005 15.4498005 15.4498005 ZT16-19 15.910889000000001 15.910889000000001 15.910889000000001 ZT20-23 16.407195 16.407195 16.407195