condition mean min max ZT0-3 7.678308333333333 6.6280149999999995 8.995505 ZT4-7 8.690095 8.690095 8.690095 ZT8-11 10.942535 10.942535 10.942535 ZT12-15 13.648525 11.27075 16.0263 ZT16-19 15.211950000000002 15.211950000000002 15.211950000000002 ZT20-23 16.826900000000002 16.826900000000002 16.826900000000002