condition mean min max ZT0-3 2.938006833333333 1.7762155 4.36086 ZT4-7 7.546305 7.546305 7.546305 ZT8-11 3.46188 3.46188 3.46188 ZT12-15 7.8866075 6.20466 9.568555 ZT16-19 5.7738 5.7738 5.7738 ZT20-23 2.328425 2.328425 2.328425