condition mean min max ZT0-3 7.910801 7.910801 7.910801 ZT4-7 8.944920499999998 8.944920499999998 8.944920499999998 ZT8-11 8.449601999999999 8.449601999999999 8.449601999999999 ZT12-15 7.247567 7.247567 7.247567 ZT16-19 8.557046 8.557046 8.557046 ZT20-23 7.832955500000001 7.832955500000001 7.832955500000001