condition mean min max ZT0-3 7.204336666666666 4.693735 8.838815 ZT4-7 6.29826 6.29826 6.29826 ZT8-11 9.843145 9.843145 9.843145 ZT12-15 7.4304125 7.19428 7.666545 ZT16-19 9.05936 9.05936 9.05936 ZT20-23 10.79645 10.79645 10.79645