condition mean min max ZT0-3 5.443525 5.443525 5.443525 ZT4-7 3.242635 3.242635 3.242635 ZT8-11 3.0409249999999997 3.0409249999999997 3.0409249999999997 ZT12-15 3.5996550000000003 3.5996550000000003 3.5996550000000003 ZT16-19 3.731295 3.731295 3.731295 ZT20-23 3.3783950000000003 3.3783950000000003 3.3783950000000003