condition mean min max ZT0-3 10.759861 10.759861 10.759861 ZT4-7 9.3291845 9.3291845 9.3291845 ZT8-11 9.500948 9.500948 9.500948 ZT12-15 8.597584999999999 8.597584999999999 8.597584999999999 ZT16-19 8.8748935 8.8748935 8.8748935 ZT20-23 10.264517 10.264517 10.264517