condition mean min max ZT0-3 9.671989 9.671989 9.671989 ZT4-7 9.1414115 9.1414115 9.1414115 ZT8-11 11.829701 11.829701 11.829701 ZT12-15 10.5041905 10.5041905 10.5041905 ZT16-19 9.053858 9.053858 9.053858 ZT20-23 8.9931725 8.9931725 8.9931725