condition mean min max ZT0-3 9.156872 9.156872 9.156872 ZT4-7 11.0105115 11.0105115 11.0105115 ZT8-11 9.3580445 9.3580445 9.3580445 ZT12-15 9.3108975 9.3108975 9.3108975 ZT16-19 11.468784 11.468784 11.468784 ZT20-23 9.079545 9.079545 9.079545