condition mean min max ZT0-3 13.880793 13.880793 13.880793 ZT4-7 12.8245825 12.8245825 12.8245825 ZT8-11 13.263516 13.263516 13.263516 ZT12-15 13.4822665 13.4822665 13.4822665 ZT16-19 11.567926499999999 11.567926499999999 11.567926499999999 ZT20-23 9.402816999999999 9.402816999999999 9.402816999999999