condition mean min max ZT0-3 8.079227500000002 7.938615 8.219840000000001 ZT4-7 5.346439999999999 5.346439999999999 5.346439999999999 ZT8-11 3.75727 3.75727 3.75727 ZT12-15 0 0 0 ZT16-19 6.23438 6.23438 6.23438 ZT20-23 7.29783 7.29783 7.29783