condition mean min max ZT0-3 6.968355000000001 6.968355000000001 6.968355000000001 ZT4-7 3.8736300000000004 3.8736300000000004 3.8736300000000004 ZT8-11 4.67566 4.67566 4.67566 ZT12-15 6.875310000000001 6.875310000000001 6.875310000000001 ZT16-19 10.224499999999999 10.224499999999999 10.224499999999999 ZT20-23 7.51604 7.51604 7.51604