condition mean min max ZT0-3 12.254076 12.254076 12.254076 ZT4-7 12.758678499999998 12.758678499999998 12.758678499999998 ZT8-11 13.2583985 13.2583985 13.2583985 ZT12-15 11.895597500000001 11.895597500000001 11.895597500000001 ZT16-19 10.9805405 10.9805405 10.9805405 ZT20-23 12.527284000000002 12.527284000000002 12.527284000000002