condition mean min max ZT0-3 3.736645 2.88911 4.58418 ZT4-7 20.381964999999997 20.381964999999997 20.381964999999997 ZT8-11 4.079845 4.079845 4.079845 ZT12-15 0 0 0 ZT16-19 9.223790000000001 9.223790000000001 9.223790000000001 ZT20-23 6.122885 6.122885 6.122885