condition mean min max ZT0-3 16.271819 16.271819 16.271819 ZT4-7 10.9355665 10.9355665 10.9355665 ZT8-11 9.1157535 9.1157535 9.1157535 ZT12-15 9.704121 9.704121 9.704121 ZT16-19 8.758288499999999 8.758288499999999 8.758288499999999 ZT20-23 9.373413500000002 9.373413500000002 9.373413500000002