condition mean min max ZT0-3 11.1984525 10.272655 12.12425 ZT4-7 7.68946 7.68946 7.68946 ZT8-11 6.091195000000001 6.091195000000001 6.091195000000001 ZT12-15 0 0 0 ZT16-19 10.520795 10.520795 10.520795 ZT20-23 11.21385 11.21385 11.21385