condition mean min max ZT0-3 80.113925 67.1828 93.04505 ZT4-7 16.9295 16.9295 16.9295 ZT8-11 11.3361 11.3361 11.3361 ZT12-15 0 0 0 ZT16-19 48.8379 48.8379 48.8379 ZT20-23 62.8124 62.8124 62.8124