condition mean min max ZT0-3 8.885548 8.885548 8.885548 ZT4-7 9.5069385 9.5069385 9.5069385 ZT8-11 9.293201 9.293201 9.293201 ZT12-15 8.6849955 8.6849955 8.6849955 ZT16-19 9.024785 9.024785 9.024785 ZT20-23 9.47146 9.47146 9.47146