condition mean min max ZT0-3 3.75015 3.75015 3.75015 ZT4-7 4.32498 4.32498 4.32498 ZT8-11 2.5083349999999998 2.5083349999999998 2.5083349999999998 ZT12-15 2.5798 2.5798 2.5798 ZT16-19 3.051515 3.051515 3.051515 ZT20-23 2.330705 2.330705 2.330705