condition mean min max ZT0-3 10.031504 10.031504 10.031504 ZT4-7 8.8312805 8.8312805 8.8312805 ZT8-11 9.352248 9.352248 9.352248 ZT12-15 9.055734000000001 9.055734000000001 9.055734000000001 ZT16-19 8.649081 8.649081 8.649081 ZT20-23 8.964916500000001 8.964916500000001 8.964916500000001