condition mean min max ZT0-3 11.737565 11.09063 12.3845 ZT4-7 7.691955 7.691955 7.691955 ZT8-11 6.047375 6.047375 6.047375 ZT12-15 0 0 0 ZT16-19 8.224205000000001 8.224205000000001 8.224205000000001 ZT20-23 9.279785 9.279785 9.279785