condition mean min max ZT0-3 3.934015 3.934015 3.934015 ZT4-7 2.230095 2.230095 2.230095 ZT8-11 3.179505 3.179505 3.179505 ZT12-15 3.99285 3.99285 3.99285 ZT16-19 6.3914550000000006 6.3914550000000006 6.3914550000000006 ZT20-23 4.5676000000000005 4.5676000000000005 4.5676000000000005