condition mean min max ZT0-3 8.081645 7.703275 8.460015 ZT4-7 6.834004999999999 6.834004999999999 6.834004999999999 ZT8-11 3.067115 3.067115 3.067115 ZT12-15 0 0 0 ZT16-19 3.385405 3.385405 3.385405 ZT20-23 4.956875 4.956875 4.956875