condition mean min max ZT0-3 2.8853066666666667 2.5990349999999998 3.02918 ZT4-7 1.4203100000000002 1.4203100000000002 1.4203100000000002 ZT8-11 1.83331 1.83331 1.83331 ZT12-15 4.3428875 4.19267 4.493105 ZT16-19 2.58606 2.58606 2.58606 ZT20-23 2.7008900000000002 2.7008900000000002 2.7008900000000002