condition mean min max ZT0-3 8.7424025 8.597435 8.88737 ZT4-7 8.07818 8.07818 8.07818 ZT8-11 6.64799 6.64799 6.64799 ZT12-15 0 0 0 ZT16-19 6.902715000000001 6.902715000000001 6.902715000000001 ZT20-23 6.08107 6.08107 6.08107