condition mean min max ZT0-3 8.344615 8.344615 8.344615 ZT4-7 4.49017 4.49017 4.49017 ZT8-11 4.148175 4.148175 4.148175 ZT12-15 5.971805 5.971805 5.971805 ZT16-19 9.051314999999999 9.051314999999999 9.051314999999999 ZT20-23 7.78631 7.78631 7.78631