condition mean min max ZT0-3 4.219735 4.219735 4.219735 ZT4-7 2.65104 2.65104 2.65104 ZT8-11 1.078585 1.078585 1.078585 ZT12-15 1.51303 1.51303 1.51303 ZT16-19 6.34293 6.34293 6.34293 ZT20-23 5.186465 5.186465 5.186465