condition mean min max ZT0-3 7.24 7.24 7.24 ZT4-7 7.036111111 7.036111111 7.036111111 ZT8-11 6.722222222 6.722222222 6.722222222 ZT12-15 6.05 6.05 6.05 ZT16-19 5.101111111 5.101111111 5.101111111 ZT20-23 5.148888888666667 5.148888888666667 5.148888888666667