condition mean min max ZT0-3 4.427026666666666 2.732375 5.4846900000000005 ZT4-7 1.463435 1.463435 1.463435 ZT8-11 2.67933 2.67933 2.67933 ZT12-15 3.9105600000000003 3.07653 4.7445900000000005 ZT16-19 3.59955 3.59955 3.59955 ZT20-23 6.461985 6.461985 6.461985