condition mean min max ZT0-3 8.820076666666667 8.223324999999999 9.615655 ZT4-7 9.03379 9.03379 9.03379 ZT8-11 15.655249999999999 15.655249999999999 15.655249999999999 ZT12-15 14.125725 13.780850000000001 14.4706 ZT16-19 12.3167 12.3167 12.3167 ZT20-23 13.7851 13.7851 13.7851