condition mean min max ZT0-3 3.0414316666666665 2.83538 3.32932 ZT4-7 3.5987400000000003 3.5987400000000003 3.5987400000000003 ZT8-11 3.3332949999999997 3.3332949999999997 3.3332949999999997 ZT12-15 5.57877 5.02206 6.135479999999999 ZT16-19 3.6361350000000003 3.6361350000000003 3.6361350000000003 ZT20-23 3.789625 3.789625 3.789625