condition mean min max ZT0-3 2.2813083333333335 2.1576 2.523485 ZT4-7 2.577015 2.577015 2.577015 ZT8-11 5.02081 5.02081 5.02081 ZT12-15 4.1940525 3.689325 4.69878 ZT16-19 5.26238 5.26238 5.26238 ZT20-23 4.222049999999999 4.222049999999999 4.222049999999999