condition mean min max ZT0-3 9.22638 9.22638 9.22638 ZT4-7 9.1879685 9.1879685 9.1879685 ZT8-11 8.736104000000001 8.736104000000001 8.736104000000001 ZT12-15 8.811223 8.811223 8.811223 ZT16-19 9.2983505 9.2983505 9.2983505 ZT20-23 8.4167775 8.4167775 8.4167775