condition mean min max ZT0-3 8.7962475 8.140329999999999 9.452165 ZT4-7 7.986235 7.986235 7.986235 ZT8-11 10.377245 10.377245 10.377245 ZT12-15 0 0 0 ZT16-19 11.60844 11.60844 11.60844 ZT20-23 8.733844999999999 8.733844999999999 8.733844999999999