condition mean min max ZT0-3 7.3846 6.921715 7.935655000000001 ZT4-7 6.855169999999999 6.855169999999999 6.855169999999999 ZT8-11 11.992535 11.992535 11.992535 ZT12-15 20.528200000000002 20.503700000000002 20.5527 ZT16-19 13.29175 13.29175 13.29175 ZT20-23 13.1283 13.1283 13.1283