condition mean min max ZT0-3 4.926395 3.491075 6.04279 ZT4-7 3.169135 3.169135 3.169135 ZT8-11 3.8510400000000002 3.8510400000000002 3.8510400000000002 ZT12-15 5.156929999999999 4.89037 5.423489999999999 ZT16-19 5.34487 5.34487 5.34487 ZT20-23 5.87235 5.87235 5.87235