condition mean min max ZT0-3 2.9876175 2.91894 3.056295 ZT4-7 3.2935499999999998 3.2935499999999998 3.2935499999999998 ZT8-11 3.311425 3.311425 3.311425 ZT12-15 0 0 0 ZT16-19 3.673435 3.673435 3.673435 ZT20-23 4.23659 4.23659 4.23659