condition mean min max ZT0-3 7.4892125 6.742865 8.23556 ZT4-7 8.038250000000001 8.038250000000001 8.038250000000001 ZT8-11 7.04953 7.04953 7.04953 ZT12-15 0 0 0 ZT16-19 8.743179999999999 8.743179999999999 8.743179999999999 ZT20-23 9.31237 9.31237 9.31237