condition mean min max ZT0-3 13.615643 13.615643 13.615643 ZT4-7 12.3445575 12.3445575 12.3445575 ZT8-11 11.832762500000001 11.832762500000001 11.832762500000001 ZT12-15 9.884292 9.884292 9.884292 ZT16-19 12.100856499999999 12.100856499999999 12.100856499999999 ZT20-23 12.464963999999998 12.464963999999998 12.464963999999998