condition mean min max ZT0-3 8.179258 8.179258 8.179258 ZT4-7 8.7307935 8.7307935 8.7307935 ZT8-11 8.307321 8.307321 8.307321 ZT12-15 8.141862 8.141862 8.141862 ZT16-19 8.5832665 8.5832665 8.5832665 ZT20-23 8.012055499999999 8.012055499999999 8.012055499999999