condition mean min max ZT0-3 2.6451575 2.593225 2.69709 ZT4-7 2.77968 2.77968 2.77968 ZT8-11 2.2615049999999997 2.2615049999999997 2.2615049999999997 ZT12-15 0 0 0 ZT16-19 5.92684 5.92684 5.92684 ZT20-23 6.392905000000001 6.392905000000001 6.392905000000001