condition mean min max ZT0-3 19.914925 19.3848 20.445050000000002 ZT4-7 17.41415 17.41415 17.41415 ZT8-11 12.08445 12.08445 12.08445 ZT12-15 0 0 0 ZT16-19 17.88275 17.88275 17.88275 ZT20-23 17.78445 17.78445 17.78445