condition mean min max ZT0-3 3.8300300000000003 3.8300300000000003 3.8300300000000003 ZT4-7 2.8589700000000002 2.8589700000000002 2.8589700000000002 ZT8-11 7.65217 7.65217 7.65217 ZT12-15 8.220695 8.220695 8.220695 ZT16-19 7.166783333333334 7.166783333333334 7.166783333333334 ZT20-23 3.9018 3.9018 3.9018