condition mean min max ZT0-3 7.382092500000001 7.1554400000000005 7.608745 ZT4-7 5.472905 5.472905 5.472905 ZT8-11 6.20982 6.20982 6.20982 ZT12-15 0 0 0 ZT16-19 7.7749749999999995 7.7749749999999995 7.7749749999999995 ZT20-23 8.180204999999999 8.180204999999999 8.180204999999999