condition mean min max ZT0-3 8.807511 8.807511 8.807511 ZT4-7 9.4497945 9.4497945 9.4497945 ZT8-11 9.1824595 9.1824595 9.1824595 ZT12-15 10.190702 10.190702 10.190702 ZT16-19 10.779741 10.779741 10.779741 ZT20-23 9.6619595 9.6619595 9.6619595