condition mean min max ZT0-3 16.68615 16.68615 16.68615 ZT4-7 8.827265 8.827265 8.827265 ZT8-11 11.0994 11.0994 11.0994 ZT12-15 9.739035000000001 9.739035000000001 9.739035000000001 ZT16-19 19.496850000000002 19.496850000000002 19.496850000000002 ZT20-23 12.59555 12.59555 12.59555