condition mean min max ZT0-3 6.808157 6.808157 6.808157 ZT4-7 8.6945405 8.6945405 8.6945405 ZT8-11 8.0797555 8.0797555 8.0797555 ZT12-15 7.618441000000001 7.618441000000001 7.618441000000001 ZT16-19 8.73751 8.73751 8.73751 ZT20-23 9.446018500000001 9.446018500000001 9.446018500000001