condition mean min max ZT0-3 5.33591 5.33591 5.33591 ZT4-7 4.91323 4.91323 4.91323 ZT8-11 2.614275 2.614275 2.614275 ZT12-15 3.58074 3.58074 3.58074 ZT16-19 6.396215 6.396215 6.396215 ZT20-23 6.336515 6.336515 6.336515