condition mean min max ZT0-3 8.10987 7.1937750000000005 9.464995 ZT4-7 7.53481 7.53481 7.53481 ZT8-11 7.85666 7.85666 7.85666 ZT12-15 7.4224025000000005 6.83107 8.013735 ZT16-19 7.1914 7.1914 7.1914 ZT20-23 7.878105 7.878105 7.878105